diff --git a/.github/workflows/run_testsuite_workflow.yml b/.github/workflows/run_testsuite_workflow.yml
index 447a459d8..ddf2f9cfe 100644
--- a/.github/workflows/run_testsuite_workflow.yml
+++ b/.github/workflows/run_testsuite_workflow.yml
@@ -59,7 +59,7 @@ jobs:
         rm -rf ./*
         rm -rf ./.??*
         ls -la ./
-    - name: Check out Tutorials for them system tests (tools/tests/)
+    - name: Check out Tutorials for the system tests (tools/tests/)
       uses: actions/checkout@v4
       with:
         repository: precice/tutorials
diff --git a/.github/workflows/system-tests-pr.yml b/.github/workflows/system-tests-pr.yml
index 920b7fab5..f7d0531f9 100644
--- a/.github/workflows/system-tests-pr.yml
+++ b/.github/workflows/system-tests-pr.yml
@@ -109,6 +109,7 @@ jobs:
           echo "\`\`\`" >> $GITHUB_STEP_SUMMARY
           echo "### Tutorials" >> $GITHUB_STEP_SUMMARY
           echo "Reference (pull request): \`${{ github.event.pull_request.head.sha }}\`" >> $GITHUB_STEP_SUMMARY
+          echo "Pull request number: [${{ github.event.number }}](https://github.com/precice/tutorials/pull/${{ github.event.number }})" >> $GITHUB_STEP_SUMMARY
 
   run-system-tests:
     name: Trigger system tests
@@ -127,6 +128,7 @@ jobs:
         OPENFOAM_ADAPTER_REF:${{ needs.gather-refs.outputs.ref-openfoam-adapter }},\
         SU2_VERSION:7.5.1,\
         SU2_ADAPTER_REF:${{ needs.gather-refs.outputs.ref-su2-adapter }},\
+        TUTORIALS_PR:${{ github.event.number }},\
         TUTORIALS_REF:${{ github.event.pull_request.head.sha }}"
       system_tests_branch: develop
       log_level: "INFO"
\ No newline at end of file
diff --git a/changelog-entries/638.md b/changelog-entries/638.md
new file mode 100644
index 000000000..7c77b1a05
--- /dev/null
+++ b/changelog-entries/638.md
@@ -0,0 +1 @@
+- Added support for running the system tests in forks [#638](https://github.com/precice/tutorials/pull/638)
\ No newline at end of file
diff --git a/tools/tests/components.yaml b/tools/tests/components.yaml
index 904c035ec..74da0c6c4 100644
--- a/tools/tests/components.yaml
+++ b/tools/tests/components.yaml
@@ -2,15 +2,15 @@ bare: # A default component used when the solver does not have any dependencies
   repository: https://github.com/precice/precice
   template: component-templates/bare.yaml
   build_arguments: # these things mean something to the docker-service
+    PLATFORM:
+      description: Dockerfile platform used
+      default: "ubuntu_2404"
     PRECICE_REF:
       description: Version of preCICE to use
       default: "main"
     PRECICE_PRESET:
       description: CMake preset of preCICE
       default: "production-audit"
-    PLATFORM:
-      description: Dockerfile platform used
-      default: "ubuntu_2404"
     TUTORIALS_REF:
       description: Tutorial git reference to use
       default: "master"
@@ -19,35 +19,35 @@ python-bindings:
   repository: https://github.com/precice/python-bindings
   template: component-templates/python-bindings.yaml
   build_arguments:
+    PLATFORM:
+      description: Dockerfile platform used
+      default: "ubuntu_2404"
     PRECICE_REF:
       description: Version of preCICE to use
       default: "main"
     PRECICE_PRESET:
       description: CMake preset of preCICE
       default: "production-audit"
-    PLATFORM:
-      description: Dockerfile platform used
-      default: "ubuntu_2404"
     TUTORIALS_REF:
       description: Tutorial git reference to use
       default: "master"
     PYTHON_BINDINGS_REF:
-      semnantic: Git ref of the pythonbindings to use
+      semnantic: Git ref of the Python bindings to use
       default: "master"
 
 openfoam-adapter:
   repository: https://github.com/precice/openfoam-adapter
   template: component-templates/openfoam-adapter.yaml
   build_arguments:
+    PLATFORM:
+      description: Dockerfile platform used
+      default: "ubuntu_2404"
     PRECICE_REF:
       description: Version of preCICE to use
       default: "main"
     PRECICE_PRESET:
       description: CMake preset of preCICE
       default: "production-audit"
-    PLATFORM:
-      description: Dockerfile platform used
-      default: "ubuntu_2404"
     TUTORIALS_REF:
       description: Tutorial git reference to use
       default: "master"
@@ -56,28 +56,27 @@ openfoam-adapter:
       description: exectuable of openfoam to use
       default: "openfoam2306"
     OPENFOAM_ADAPTER_REF:
-      description: Reference/tag of the actual OpenFOAM adapter
+      description: Reference/tag of the OpenFOAM adapter to use
       default: "master"
 
-    
 fenics-adapter:
   repository: https://github.com/precice/fenics-adapter
   template: component-templates/fenics-adapter.yaml
   build_arguments:
+    PLATFORM:
+      description: Dockerfile platform used
+      default: "ubuntu_2404"
     PRECICE_REF:
       description: Version of preCICE to use
       default: "main"
     PRECICE_PRESET:
       description: CMake preset of preCICE
       default: "production-audit"
-    PLATFORM:
-      description: Dockerfile platform used
-      default: "ubuntu_2404"
     TUTORIALS_REF:
       description: Tutorial git reference to use
       default: "master"
     PYTHON_BINDINGS_REF:
-      semnantic: Git ref of the pythonbindings to use
+      semnantic: Git ref of the Python bindings to use
       default: "master"
     FENICS_ADAPTER_REF:
       semnantic: Git ref of the fenics adapter to use
@@ -87,35 +86,35 @@ nutils-adapter:
   repository: https://github.com/precice/nutils-adapter
   template: component-templates/nutils-adapter.yaml
   build_arguments:
+    PLATFORM:
+      description: Dockerfile platform used
+      default: "ubuntu_2404"
     PRECICE_REF:
       description: Version of preCICE to use
       default: "main"
     PRECICE_PRESET:
       description: CMake preset of preCICE
       default: "production-audit"
-    PLATFORM:
-      description: Dockerfile platform used
-      default: "ubuntu_2404"
     TUTORIALS_REF:
       description: Tutorial git reference to use
       default: "master"
     PYTHON_BINDINGS_REF:
-      semnantic: Git ref of the pythonbindings to use
-
+      semnantic: Git ref of the Python bindings to use
+      default: "master"
 
 calculix-adapter:
   repository: https://github.com/precice/calculix-adapter
   template: component-templates/calculix-adapter.yaml
   build_arguments:
+    PLATFORM:
+      description: Dockerfile platform used
+      default: "ubuntu_2404"
     PRECICE_REF:
       description: Version of preCICE to use
       default: "main"
     PRECICE_PRESET:
       description: CMake preset of preCICE
       default: "production-audit"
-    PLATFORM:
-      description: Dockerfile platform used
-      default: "ubuntu_2404"
     TUTORIALS_REF:
       description: Tutorial git reference to use
       default: "master"
@@ -130,15 +129,15 @@ su2-adapter:
   repository: https://github.com/precice/su2-adapter
   template: component-templates/su2-adapter.yaml
   build_arguments:
+    PLATFORM:
+      description: Dockerfile platform used
+      default: "ubuntu_2404"
     PRECICE_REF:
       description: Version of preCICE to use
       default: "main"
     PRECICE_PRESET:
       description: CMake preset of preCICE
       default: "production-audit"
-    PLATFORM:
-      description: Dockerfile platform used
-      default: "ubuntu_2404"
     TUTORIALS_REF:
       description: Tutorial git reference to use
       default: "master"
diff --git a/tools/tests/dockerfiles/ubuntu_2204/Dockerfile b/tools/tests/dockerfiles/ubuntu_2204/Dockerfile
index b20eeb57c..4b313e7d4 100644
--- a/tools/tests/dockerfiles/ubuntu_2204/Dockerfile
+++ b/tools/tests/dockerfiles/ubuntu_2204/Dockerfile
@@ -47,12 +47,14 @@ RUN python3 -m pip install --user --upgrade pip
 
 FROM precice_dependecies AS precice
 # Install & build precice into /home/precice/precice
+ARG PRECICE_PR
 ARG PRECICE_REF
 ARG PRECICE_PRESET
 USER precice
 WORKDIR /home/precice
 RUN git clone https://github.com/precice/precice.git precice && \
     cd precice && \
+    if [ -n "${PRECICE_PR}" ]; then git fetch origin pull/${PRECICE_PR}/head; fi && \
     git checkout ${PRECICE_REF} && \
     mkdir build && cd build &&\
     cmake .. --preset=${PRECICE_PRESET} -DCMAKE_INSTALL_PREFIX=/home/precice/.local/ -DPRECICE_PETScMapping=OFF -DBUILD_TESTING=OFF && \
@@ -67,12 +69,14 @@ RUN apt-get update &&\
     ln -s $(which ${OPENFOAM_EXECUTABLE} ) /usr/bin/openfoam
 USER precice
 COPY --from=precice /home/precice/.local/ /home/precice/.local/
+ARG OPENFOAM_ADAPTER_PR
 ARG OPENFOAM_ADAPTER_REF
 # Build the OpenFOAM adapter 
 USER precice
 WORKDIR /home/precice
 RUN git clone https://github.com/precice/openfoam-adapter.git &&\
     cd openfoam-adapter && \
+    if [ -n "${OPENFOAM_ADAPTER_PR}" ]; then git fetch origin pull/${OPENFOAM_ADAPTER_PR}/head; fi && \
     git checkout ${OPENFOAM_ADAPTER_REF} && \
     /usr/bin/${OPENFOAM_EXECUTABLE} ./Allwmake -j $(nproc)
 
@@ -119,10 +123,12 @@ RUN wget http://www.dhondt.de/ccx_${CALCULIX_VERSION}.src.tar.bz2 && \
     tar xvjf ccx_${CALCULIX_VERSION}.src.tar.bz2 && \
     rm -fv ccx_${CALCULIX_VERSION}.src.tar.bz2
 
+ARG CALCULIX_ADAPTER_PR
 ARG CALCULIX_ADAPTER_REF
 WORKDIR /home/precice
 RUN git clone https://github.com/precice/calculix-adapter.git && \
     cd calculix-adapter && \
+    if [ -n "${CALCULIX_ADAPTER_PR}" ]; then git fetch origin pull/${CALCULIX_ADAPTER_PR}/head; fi && \
     git checkout ${CALCULIX_ADAPTER_REF} &&\
     make CXX_VERSION=${CALCULIX_VERSION} ADDITIONAL_FFLAGS="-fallow-argument-mismatch" -j $(nproc) && \
     ln -s /home/precice/calculix-adapter/bin/ccx_preCICE /home/precice/.local/bin/ccx_preCICE
@@ -141,6 +147,7 @@ RUN wget https://github.com/su2code/SU2/archive/refs/tags/v${SU2_VERSION}.tar.gz
     tar xvzf v${SU2_VERSION}.tar.gz && \
     rm -fv v${SU2_VERSION}.tar.gz
 RUN pip3 install --user mpi4py
+ARG SU2_ADAPTER_PR
 ARG SU2_ADAPTER_REF
 WORKDIR /home/precice
 ENV SU2_RUN="/home/precice/SU2_RUN" 
@@ -149,6 +156,7 @@ ENV PATH="/home/precice/su2-adapter/run:$SU2_RUN:$PATH"
 ENV PYTHONPATH="$SU2_RUN:$PYTHONPATH"
 RUN git clone https://github.com/precice/su2-adapter.git && \
     cd su2-adapter &&\
+    if [ -n "${SU2_ADAPTER_PR}" ]; then git fetch origin pull/${SU2_ADAPTER_PR}/head; fi && \
     git checkout ${SU2_ADAPTER_REF} &&\
     ./su2AdapterInstall
 RUN cd "${SU2_HOME}" &&\
diff --git a/tools/tests/dockerfiles/ubuntu_2404/Dockerfile b/tools/tests/dockerfiles/ubuntu_2404/Dockerfile
index 50c55ada0..11f4657c1 100644
--- a/tools/tests/dockerfiles/ubuntu_2404/Dockerfile
+++ b/tools/tests/dockerfiles/ubuntu_2404/Dockerfile
@@ -45,12 +45,14 @@ USER precice
 
 FROM precice_dependecies AS precice
 # Install & build precice into /home/precice/precice
+ARG PRECICE_PR
 ARG PRECICE_REF
 ARG PRECICE_PRESET
 USER precice
 WORKDIR /home/precice
 RUN git clone https://github.com/precice/precice.git precice && \
     cd precice && \
+    if [ -n "${PRECICE_PR}" ]; then git fetch origin pull/${PRECICE_PR}/head; fi && \
     git checkout ${PRECICE_REF} && \
     mkdir build && cd build &&\
     cmake .. --preset=${PRECICE_PRESET} -DCMAKE_INSTALL_PREFIX=/home/precice/.local/ -DPRECICE_PETScMapping=OFF -DBUILD_TESTING=OFF && \
@@ -65,12 +67,14 @@ RUN apt-get update &&\
     ln -s $(which ${OPENFOAM_EXECUTABLE} ) /usr/bin/openfoam
 USER precice
 COPY --from=precice /home/precice/.local/ /home/precice/.local/
+ARG OPENFOAM_ADAPTER_PR
 ARG OPENFOAM_ADAPTER_REF
 # Build the OpenFOAM adapter 
 USER precice
 WORKDIR /home/precice
 RUN git clone https://github.com/precice/openfoam-adapter.git &&\
     cd openfoam-adapter && \
+    if [ -n "${OPENFOAM_ADAPTER_PR}" ]; then git fetch origin pull/${OPENFOAM_ADAPTER_PR}/head; fi && \
     git checkout ${OPENFOAM_ADAPTER_REF} && \
     /usr/bin/${OPENFOAM_EXECUTABLE} ./Allwmake -j $(nproc)
 
@@ -123,10 +127,12 @@ RUN wget http://www.dhondt.de/ccx_${CALCULIX_VERSION}.src.tar.bz2 && \
     tar xvjf ccx_${CALCULIX_VERSION}.src.tar.bz2 && \
     rm -fv ccx_${CALCULIX_VERSION}.src.tar.bz2
 
+ARG CALCULIX_ADAPTER_PR
 ARG CALCULIX_ADAPTER_REF
 WORKDIR /home/precice
 RUN git clone https://github.com/precice/calculix-adapter.git && \
     cd calculix-adapter && \
+    if [ -n "${CALCULIX_ADAPTER_PR}" ]; then git fetch origin pull/${CALCULIX_ADAPTER_PR}/head; fi && \
     git checkout ${CALCULIX_ADAPTER_REF} &&\
     make CXX_VERSION=${CALCULIX_VERSION} ADDITIONAL_FFLAGS="-fallow-argument-mismatch" -j $(nproc) && \
     ln -s /home/precice/calculix-adapter/bin/ccx_preCICE /home/precice/.local/bin/ccx_preCICE
@@ -147,6 +153,7 @@ RUN wget https://github.com/su2code/SU2/archive/refs/tags/v${SU2_VERSION}.tar.gz
     rm -fv v${SU2_VERSION}.tar.gz
 RUN python3 -m venv /home/precice/venv && \
     . /home/precice/venv/bin/activate
+ARG SU2_ADAPTER_PR
 ARG SU2_ADAPTER_REF
 WORKDIR /home/precice
 ENV SU2_RUN="/home/precice/SU2_RUN" 
@@ -155,6 +162,7 @@ ENV PATH="/home/precice/su2-adapter/run:$SU2_RUN:$PATH"
 ENV PYTHONPATH="$SU2_RUN:$PYTHONPATH"
 RUN git clone https://github.com/precice/su2-adapter.git && \
     cd su2-adapter &&\
+    if [ -n "${SU2_ADAPTER_PR}" ]; then git fetch origin pull/${SU2_ADAPTER_PR}/head; fi && \
     git checkout ${SU2_ADAPTER_REF} &&\
     ./su2AdapterInstall
 RUN cd "${SU2_HOME}" &&\
diff --git a/tools/tests/systemtests/Systemtest.py b/tools/tests/systemtests/Systemtest.py
index 49e30f2e8..78ff9680f 100644
--- a/tools/tests/systemtests/Systemtest.py
+++ b/tools/tests/systemtests/Systemtest.py
@@ -146,30 +146,26 @@ def __post_init__(self):
 
     def __init_args_to_use(self):
         """
-        Checks if all required parameters for the realisation of the cases are supplied in the cmdline arguments.
-        If a parameter is missing and it's required, an exception is raised.
-        Otherwise, the default value is used if available.
+        Forwards the command-line arguments to the params_to_use dictionary, substituting any missing arguments with their defaults.
 
-        In the end it populates the args_to_use dict
-
-        Raises:
-            Exception: If a required parameter is missing.
+        Previously, this function was also checking if all required parameters were provided, and was raising exceptions for parameters not provided and not having a default value. This check made adding optional parameters with empty defaults (e.g., the TUTORIALS_PR) complicated, and it was removed.
         """
-        self.params_to_use = {}
+
+        # Forward all provided arguments to params_to_use
+        provided_arguments = self.arguments.arguments
+        self.params_to_use = provided_arguments
+
+        # Find out which parameters are needed
         needed_parameters = set()
         for case in self.case_combination.cases:
             needed_parameters.update(case.component.parameters)
 
+        # Substitute defaults for non-provided, needed arguments
         for needed_param in needed_parameters:
-            if self.arguments.contains(needed_param.key):
-                self.params_to_use[needed_param.key] = self.arguments.get(
-                    needed_param.key)
-            else:
-                if needed_param.required:
-                    raise Exception(
-                        f"{needed_param} is needed to be given via --params to instantiate the systemtest for {self.tutorial.name}")
-                else:
-                    self.params_to_use[needed_param.key] = needed_param.default
+            if not needed_param.key in provided_arguments:
+                logging.warning(
+                    f"No argument provided for needed parameter {needed_param.key}. Substituting with {needed_param.default}")
+                self.params_to_use[needed_param.key] = needed_param.default
 
     def __get_docker_services(self) -> Dict[str, str]:
         """
@@ -249,6 +245,19 @@ def _get_git_ref(self, repository: Path, abbrev_ref=False) -> Optional[str]:
         except Exception as e:
             raise RuntimeError(f"An error occurred while getting the current Git ref: {e}") from e
 
+    def _fetch_pr(self, repository: Path, pr: str):
+        try:
+            result = subprocess.run([
+                "git",
+                "-C", os.fspath(repository.resolve()),
+                "fetch",
+                "origin",
+                "pull/" + pr + "/head"
+            ], check=True, timeout=60)
+
+        except Exception as e:
+            raise RuntimeError(f"git command returned code {result.returncode}")
+
     def _fetch_ref(self, repository: Path, ref: str):
         try:
             result = subprocess.run([
@@ -282,6 +291,10 @@ def __copy_tutorial_into_directory(self, run_directory: Path):
         """
         current_time_string = datetime.now().strftime('%Y-%m-%d %H:%M:%S')
         self.run_directory = run_directory
+        pr_requested = self.params_to_use.get("TUTORIALS_PR")
+        if pr_requested:
+            logging.debug(f"Fetching the PR {pr_requested} HEAD reference")
+            self._fetch_pr(PRECICE_TUTORIAL_DIR, pr_requested)
         current_ref = self._get_git_ref(PRECICE_TUTORIAL_DIR)
         ref_requested = self.params_to_use.get("TUTORIALS_REF")
         if ref_requested: