diff --git a/gradle-plugins/cordformation/src/main/groovy/net/corda/plugins/Node.groovy b/gradle-plugins/cordformation/src/main/groovy/net/corda/plugins/Node.groovy
index d1fee783e8..3b64b31704 100644
--- a/gradle-plugins/cordformation/src/main/groovy/net/corda/plugins/Node.groovy
+++ b/gradle-plugins/cordformation/src/main/groovy/net/corda/plugins/Node.groovy
@@ -75,8 +75,8 @@ class Node {
         config = config.withValue("useHTTPS", ConfigValueFactory.fromAnyRef(isHttps))
     }
 
-    void useTestClock() {
-        config = config.withValue("useTestClock", ConfigValueFactory.fromAnyRef(true))
+    void useTestClock(Boolean useTestClock) {
+        config = config.withValue("useTestClock", ConfigValueFactory.fromAnyRef(useTestClock))
     }
 
     /**
diff --git a/samples/irs-demo/build.gradle b/samples/irs-demo/build.gradle
index f242e0dde7..b0e4283c84 100644
--- a/samples/irs-demo/build.gradle
+++ b/samples/irs-demo/build.gradle
@@ -89,7 +89,7 @@ task deployNodes(type: net.corda.plugins.Cordform, dependsOn: [':install', 'buil
         artemisPort 10002
         webPort 10003
         cordapps = []
-        useTestClock()
+        useTestClock true
     }
     node {
         name "Bank A"
@@ -99,7 +99,7 @@ task deployNodes(type: net.corda.plugins.Cordform, dependsOn: [':install', 'buil
         artemisPort 10004
         webPort 10005
         cordapps = []
-        useTestClock()
+        useTestClock true
     }
     node {
         name "Bank B"
@@ -109,7 +109,7 @@ task deployNodes(type: net.corda.plugins.Cordform, dependsOn: [':install', 'buil
         artemisPort 10006
         webPort 10007
         cordapps = []
-        useTestClock()
+        useTestClock true
     }
 }