diff --git a/infrastructure/modules/s3/main.tf b/infrastructure/modules/s3/main.tf
index d48cf86e..2e985787 100755
--- a/infrastructure/modules/s3/main.tf
+++ b/infrastructure/modules/s3/main.tf
@@ -57,7 +57,7 @@ module "s3" {
 }
 
 resource "aws_s3_bucket_policy" "enforce_kms_truststore" {
-  count  = var.enable_kms_encryption ? 1 : 0
+  count  = var.enable_kms_encryption && var.enable_kms_bucket_policy ? 1 : 0
   bucket = module.s3.s3_bucket_id
   policy = jsonencode({ Version = "2012-10-17"
     Statement = [
diff --git a/infrastructure/modules/s3/variables.tf b/infrastructure/modules/s3/variables.tf
index a5fa0f58..bb5157f2 100755
--- a/infrastructure/modules/s3/variables.tf
+++ b/infrastructure/modules/s3/variables.tf
@@ -34,8 +34,18 @@ variable "bucket_name" {
 #   description = "The path to the zip file"
 #   type        = string
 # }
-variable "attach_policy" { default = false }
-variable "policy" { default = null }
+variable "attach_policy" {
+  description = "Whether to attach a policy to the s3 bucket"
+  type        = bool
+  default     = false
+}
+
+variable "policy" {
+  description = "s3 bucket policy as a JSON string"
+  type        = string
+  default     = null
+}
+
 variable "lifecycle_rule_inputs" { default = [] }
 
 variable "target_access_logging_bucket" {
@@ -82,3 +92,9 @@ variable "enable_kms_encryption" {
   type        = bool
   default     = false
 }
+
+variable "enable_kms_bucket_policy" {
+  description = "Whether to attach the KMS enforcement bucket policy. Disable if managing policy externally"
+  type        = bool
+  default     = true
+}
diff --git a/infrastructure/stacks/artefact_management/s3.tf b/infrastructure/stacks/artefact_management/s3.tf
index ad928fa7..598c2983 100644
--- a/infrastructure/stacks/artefact_management/s3.tf
+++ b/infrastructure/stacks/artefact_management/s3.tf
@@ -34,22 +34,18 @@ locals {
   all_bucket_principals = flatten(values(local.principals_by_environment))
 }
 
-
 module "artefacts_bucket" {
   source      = "../../modules/s3"
   bucket_name = local.artefacts_bucket
-  enable_kms_encryption = true
-  s3_encryption_key_arn = module.s3_artefacts_encryption_key.arn
-}
-
-
-resource "aws_s3_bucket_policy" "artefacts_bucket_policy" {
-  depends_on = [module.artefacts_bucket]
-  bucket     = local.artefacts_bucket
-  policy     = data.aws_iam_policy_document.artefacts_bucket_policy.json
+  enable_kms_encryption    = true
+  s3_encryption_key_arn    = module.s3_artefacts_encryption_key.arn
+  attach_policy            = true
+  policy                   = data.aws_iam_policy_document.artefacts_bucket_policy.json
+  enable_kms_bucket_policy = false
 }
 
 data "aws_iam_policy_document" "artefacts_bucket_policy" {
+
   statement {
     principals {
       type = "AWS"
@@ -79,4 +75,36 @@ data "aws_iam_policy_document" "artefacts_bucket_policy" {
       "${module.artefacts_bucket.s3_bucket_arn}/*",
     ]
   }
+
+  statement {
+    sid = "DenyUnencryptedUploads"
+    effect = "Deny"
+    principals {
+      type = "AWS"
+      identifiers = ["*"]
+    }
+    actions = ["s3:PutObject"]
+    resources = ["${module.artefacts_bucket.s3_bucket_arn}/*"]
+    condition {
+      test     = "StringNotEquals"
+      variable = "s3:x-amz-server-side-encryption"
+      values   = ["aws:kms"]
+    }
+  }
+
+  statement {
+    sid = "DenyUnencryptedKMSUploads"
+    effect = "Deny"
+    principals {
+      type = "AWS"
+      identifiers = ["*"]
+    }
+    actions = ["s3:PutObject"]
+    resources = ["${module.artefacts_bucket.s3_bucket_arn}/*"]
+    condition {
+      test     = "ArnNotEquals"
+      variable = "s3:x-amz-server-side-encryption-aws-kms-key-id"
+      values   = ["module.s3_artefacts_encryption_key.arn"]
+    }
+  }
 }
diff --git a/infrastructure/stacks/github_runner/account_github_runner_data.policy.json.tpl b/infrastructure/stacks/github_runner/account_github_runner_data.policy.json.tpl
index ebdb1a5f..2f9dabe9 100644
--- a/infrastructure/stacks/github_runner/account_github_runner_data.policy.json.tpl
+++ b/infrastructure/stacks/github_runner/account_github_runner_data.policy.json.tpl
@@ -76,7 +76,8 @@
             "Sid": "TerraformStateLockingDynamoTable",
             "Effect": "Allow",
             "Action": [
-                "dynamodb:DeleteItem",
+                "dynamodb:Delete*",
+                "dynamodb:Create*",
                 "dynamodb:Describe*",
                 "dynamodb:Get*",
                 "dynamodb:List*",
diff --git a/infrastructure/stacks/github_runner/app_github_runner_data.policy.json.tpl b/infrastructure/stacks/github_runner/app_github_runner_data.policy.json.tpl
index 99f16b89..5a7c2920 100644
--- a/infrastructure/stacks/github_runner/app_github_runner_data.policy.json.tpl
+++ b/infrastructure/stacks/github_runner/app_github_runner_data.policy.json.tpl
@@ -83,7 +83,8 @@
             "Sid": "TerraformStateLockingDynamoTable",
             "Effect": "Allow",
             "Action": [
-                "dynamodb:DeleteItem",
+                "dynamodb:Delete*",
+                "dynamodb:Create*",
                 "dynamodb:Describe*",
                 "dynamodb:Get*",
                 "dynamodb:List*",