diff --git a/docs/src/whatsnew/latest.rst b/docs/src/whatsnew/latest.rst
index 383d029ccf..e611110ebe 100644
--- a/docs/src/whatsnew/latest.rst
+++ b/docs/src/whatsnew/latest.rst
@@ -49,6 +49,9 @@ This document explains the changes made to Iris for this release
    ``standard_parallel`` and ``scale_factor_at_projection_origin`` to
    :class:`~iris.coord_system.Mercator`. (:issue:`3844`, :pull:`4609`)
 
+#. `@wjbenfold`_ and `@stephenworsley`_ (reviewer) added a maximum run length
+   aggregator (:class:`~iris.analysis.MAX_RUN`). (:pull:`4676`)
+
 
 🐛 Bugs Fixed
 =============
diff --git a/lib/iris/analysis/__init__.py b/lib/iris/analysis/__init__.py
index 63b9173e6c..cf035d568f 100644
--- a/lib/iris/analysis/__init__.py
+++ b/lib/iris/analysis/__init__.py
@@ -64,6 +64,7 @@
     "HMEAN",
     "Linear",
     "MAX",
+    "MAX_RUN",
     "MEAN",
     "MEDIAN",
     "MIN",