Following consultation, HMRC have agreed to extend the single compliance process trial to 31 March 2012 to make sure that sufficient data has been collected to test the process fully.
Also, four more sites will be added from January 2012 to test the process and the internal implementation package further.
The Revenue said the decision to test the rollout should not been seen as an indication that a decision has been made on the future of the single compliance process.
The department confirms it is still in trial stage and lessons are being learnt on the best design of the process and its impact.