HM Revenue and Customs (HMRC) would pay a fine for every half an hour they leave hard-working British businesses on hold, Reform UK has revealed.

New policies announced by Robert Jenrick to support family firms took aim at the waiting times entrepreneurs face when calling the taxman.

Businesses spend some ยฃ25billion a year on filing their tax returns, taking around 242 million working hours to do so, Mr Jenrick claimed.

Reform’s Treasury spokesman blasted the delays, saying businessmen were spending “hours on the phone trying to give them money”, which was “enough to drive you mad”.

Should his party win the next general election and he becomes chancellor, the Reform MP said he would focus on improving the quality of the service.

“It’s a disgrace, frankly, it’s offensive to working people,” Mr Jenrick said as he announced his party would give HMRC an “incentive” to do better.

Under the proposals, the taxman would be forced to hand a ยฃ30 tax credit to businesses left waiting for more than half an hour for HMRC to answer their call.

Mandarins would also see their pay linked to customer service performance, which Mr Jenrick said was “just fair”.

He also confirmed that tax officials would need to send him a daily report on their progress, and should they “test [his] patience […] they will be fired.”

But his Labour rivals slammed the contract with small businesses as unworkable, after Mr Jenrick did not say at a press conference how much the package would cost.

Some costings were detailed in a document handed out after the event. Reform UK also pointed to an earlier announcement detailing widespread savings in the welfare system.

A Labour Party spokesman said: “Reform once again skated over the detail of their own policies because they simply don’t have the answers.

“Robert Jenrick canโ€™t say which important data safeguards he would scrap and whether it would put peopleโ€™s personal details at risk. Heโ€™s making it up as he goes along.

“With Andy Burnham’s leadership, Labour is backing small businesses, reviving our high streets and driving growth in every postcode.”