diff --git a/infrastructure/terraform/lambda/ordnanceSurvey/variables.tf b/infrastructure/terraform/lambda/ordnanceSurvey/variables.tf
index e2cfd65e..936aebc9 100644
--- a/infrastructure/terraform/lambda/ordnanceSurvey/variables.tf
+++ b/infrastructure/terraform/lambda/ordnanceSurvey/variables.tf
@@ -19,7 +19,7 @@ variable "image_digest" {
 
 variable "maximum_concurrency" {
   type        = number
-  default     = 1
+  default     = null
   description = "Maximum number of concurrent Lambda invocations from SQS (2-1000). null = no limit."
 }
 
diff --git a/infrastructure/terraform/lambda/pashub_to_ara/variables.tf b/infrastructure/terraform/lambda/pashub_to_ara/variables.tf
index fe92d645..e7646811 100644
--- a/infrastructure/terraform/lambda/pashub_to_ara/variables.tf
+++ b/infrastructure/terraform/lambda/pashub_to_ara/variables.tf
@@ -19,7 +19,7 @@ variable "image_digest" {
 
 variable "maximum_concurrency" {
   type        = number
-  default     = 1
+  default     = null
   description = "Maximum number of concurrent Lambda invocations from SQS (2-1000). null = no limit."
 }