diff --git a/infrastructure/concurrency_controls.tf b/infrastructure/concurrency_controls.tf
new file mode 100644
index 000000000..307f39dfa
--- /dev/null
+++ b/infrastructure/concurrency_controls.tf
@@ -0,0 +1,39 @@
+# Concurrency control schedules
+# These times are set to ensure 9 AM - 7 PM UK local time is always covered regardless of GMT/BST:
+# - During GMT (winter): 8 AM UTC = 8 AM local, 7 PM UTC = 7 PM local (covers 9 AM - 7 PM with buffer)
+# - During BST (summer): 8 AM UTC = 9 AM local, 7 PM UTC = 8 PM local (covers 9 AM - 7 PM with buffer)
+# This guarantees the core working hours (9 AM - 7 PM UK time) always have reduced concurrency.
+
+# Office hours start (8 AM UTC)
+resource "aws_cloudwatch_event_rule" "bulk_upload_concurrency_office_hours_start" {
+  name                = "bulk-upload-office-hours-start"
+  schedule_expression = "cron(0 8 * * ? *)"
+}
+
+resource "aws_cloudwatch_event_target" "bulk_upload_concurrency_office_hours_start" {
+  rule      = aws_cloudwatch_event_rule.bulk_upload_concurrency_office_hours_start.name
+  target_id = "office-hours-start"
+  arn       = module.concurrency-controller-lambda.lambda_arn
+
+  input = jsonencode({
+    targetFunction      = module.bulk-upload-lambda.function_name
+    reservedConcurrency = var.office_hours_start_concurrency
+  })
+}
+
+# Office hours stop (7 PM UTC / 19:00 UTC)
+resource "aws_cloudwatch_event_rule" "bulk_upload_concurrency_office_hours_stop" {
+  name                = "bulk-upload-office-hours-stop"
+  schedule_expression = "cron(0 19 * * ? *)"
+}
+
+resource "aws_cloudwatch_event_target" "bulk_upload_concurrency_office_hours_stop" {
+  rule      = aws_cloudwatch_event_rule.bulk_upload_concurrency_office_hours_stop.name
+  target_id = "office-hours-stop"
+  arn       = module.concurrency-controller-lambda.lambda_arn
+
+  input = jsonencode({
+    targetFunction      = module.bulk-upload-lambda.function_name
+    reservedConcurrency = var.office_hours_end_concurrency
+  })
+}
diff --git a/infrastructure/lambda-concurrency-controller.tf b/infrastructure/lambda-concurrency-controller.tf
new file mode 100644
index 000000000..d496c68bd
--- /dev/null
+++ b/infrastructure/lambda-concurrency-controller.tf
@@ -0,0 +1,45 @@
+
+data "aws_iam_policy_document" "concurrency_controller_policy" {
+  statement {
+    effect = "Allow"
+    actions = [
+      "lambda:PutFunctionConcurrency",
+      "lambda:GetFunctionConcurrency"
+    ]
+    resources = [
+      module.bulk-upload-lambda.lambda_arn
+    ]
+  }
+}
+
+module "concurrency-controller-lambda" {
+  source  = "./modules/lambda"
+  name    = "ConcurrencyController"
+  handler = "handlers.concurrency_controller_handler.lambda_handler"
+
+  #This lambda is an orchestrator so should have unlimited conc
+  reserved_concurrent_executions = -1
+
+  is_gateway_integration_needed = false
+  is_invoked_from_gateway       = false
+
+  iam_role_policy_documents = [
+    data.aws_iam_policy_document.concurrency_controller_policy.json
+  ]
+}
+
+resource "aws_lambda_permission" "office_hours_start_permission" {
+  statement_id  = "AllowEventBridgeOfficeHoursStart"
+  action        = "lambda:InvokeFunction"
+  function_name = module.concurrency-controller-lambda.function_name
+  principal     = "events.amazonaws.com"
+  source_arn    = aws_cloudwatch_event_rule.bulk_upload_concurrency_office_hours_start.arn
+}
+
+resource "aws_lambda_permission" "office_hours_stop_permission" {
+  statement_id  = "AllowEventBridgeOfficeHoursStop"
+  action        = "lambda:InvokeFunction"
+  function_name = module.concurrency-controller-lambda.function_name
+  principal     = "events.amazonaws.com"
+  source_arn    = aws_cloudwatch_event_rule.bulk_upload_concurrency_office_hours_stop.arn
+}
diff --git a/infrastructure/schedules.tf b/infrastructure/schedules.tf
index 5b86cbcf6..9fd00a50d 100644
--- a/infrastructure/schedules.tf
+++ b/infrastructure/schedules.tf
@@ -198,3 +198,5 @@ resource "aws_lambda_permission" "transfer_key_manager_schedule_permission" {
     aws_cloudwatch_event_rule.transfer_key_manager_schedule
   ]
 }
+
+
diff --git a/infrastructure/variable.tf b/infrastructure/variable.tf
index 272a4cbfd..20d397488 100644
--- a/infrastructure/variable.tf
+++ b/infrastructure/variable.tf
@@ -321,3 +321,17 @@ variable "ssh_key_management_dry_run" {
   type        = bool
   default     = false
 }
+
+# Concurrency Controller 
+
+variable "office_hours_start_concurrency" {
+  type    = number
+  default = 1
+}
+
+variable "office_hours_end_concurrency" {
+  type    = number
+  default = 3
+}
+
+