A Government minister was left red-faced by Philip Hammond’s Budget U-turn by finding himself defending the measure live on television as details of the change emerged.

Rory Stewart, an international development minister, was defending the National Insurance Contributions increase on the BBC’s Daily Politics programme after the programme started at 11.30am.

Pressed on the change, he said: “It is important to understand that the majority of self employed people will not be worse off as a result of this measure.

“So if you're on £17,000 a year, like the majority of my constituents, you would be £309 better off in terms of your tax at the end of this change.”

However, at 11.38am, just as he was speaking Mr Hammond’s letter to Tory MPs which informed them of the climbdown was released to the press.

The programme then moved on to discuss Labour taxation policy before AAndrew Neil, the programme’s presenter, saod that “as we've been on air”, the Chancellor had “announced that there will be no increases in national insurance contributions in this parliament”.

After his co-presenter Jo Coburn read out some of the letter, Mr Neil asked the minister: “What is it about this Government and chancellors?

“Why are they so useless? Under George Osborne they announce massive cuts in tax credits for the working class ... in the end Mr Osborne had to get rid of it all.