But not all employers have yet made the changes needed for compliance. Ellie Gamble, associate director at Grant Thornton, said: “The preparedness of employers is widely variable.

“Some have been in the pilot since day one and are saying that, after a bumpy start, they are prepared for their UK populations and [the process] is running fine. We have been advising [employers] to do the simple things, such as getting data straight and being sure they know what they need to do.”

Mark Groom, a tax partner at Deloitte, added: “Some employers just aren’t ready. In some cases, their providers have let them down because the software hasn’t been provided in time or still has glitches. However, I think HMRC has been accommodating.”

On 19 March, HMRC relaxed RTI reporting arrangements for small employers, extending the deadline until 5 October 2013 for organisations with fewer than 50 employees.