Nigel Farage reports Rachel Reeves to PM's ethics adviser after 'serious Budget breach' allegations

Mr Farage cited Ms Reeves's remarks in the House of Commons in early November and pointed out that the Chancellor had not disclosed the Office for Budget Responsibility's positive headroom forecast to MPs or the public.

The Reform UK leader also took aim at the Chancellor over her "inaccurate statements concerning her professional background", later swiping at the Prime Minister over his alleged knowledge of the Treasury's pre-Budget briefing strategy.

Mr Farage wrote: “First, it has been widely reported that, weeks before the Budget, the Office for Budget Responsibility informed the Chancellor that, on unchanged policy, she was on course to meet her fiscal rules with headroom of at least £4billion, and never less than £1.5billion.

“Secondly, notwithstanding that information, the Chancellor conducted a sustained public and media campaign portraying the public finances as being in a state of collapse in order to prepare political ground for approximately £30billion of tax increases which, on the OBR’s own numbers, were discretionary policy choices rather than unavoidable fiscal necessity.”

In a direct plea to Sir Magnus, Mr Farage added: “I therefore ask you to advise the Prime Minister without delay that this matter meets the threshold for formal investigation under the Code, and that such an investigation should begin immediately.

"Given the gravity of the allegations and the public interest, I further request confirmation within seven days whether you intend to initiate an investigation under paragraph 2.6(b) of the Code or advise the Prime Minister to refer the matter to you.”

However, Ms Reeves insisted earlier today that she did not lie to voters about a black hole in the public finances.

The Chancellor told the BBC: “I do not accept that at all. The OBR numbers themselves, which I agree with and we knew they were going to be published, they are very clear that there was less fiscal space than there was just a few months ago in the spring. And we needed not less but more fiscal headroom.”

Speaking to GB News this morning, Treasury Minister James Murray also rejected claims that the Chancellor had lied to the public about the state of Britain's finances.

"The OBR set out clearly that there had been a productivity downgrade of £16billion," Mr Murray told The Camilla Tominey Show.

"And going into the Budget process, we also knew we wanted to get headroom up, and that headroom is critical to helping to get the cost of government borrowing and to getting mortgages down."

However, Ms Reeves was informed by the OBR on October 31 that there was no deficit in the public finances, with tax receipts creating a surplus of £4.2billion before policy measures had been taken into account.

However, the Chancellor went on to use a keynote pre-Budget press conference to hint at breaking Labour's manifesto commitment not to raise taxes due to concerns about the UK's finances on November 4.

Ms Reeves is expected to face fury from MPs over claims she misled MPs and the public.

Commons Speaker Sir Lindsay Hoyle is expected to grant an urgent question if one is requested by MPs.

The Chancellor will also appear before the Treasury Select Committee on December 10.

Meanwhile, Shadow Chancellor Sir Mel Stride urged the UK's financial regulator to investigate "possible market abuse" by people working in the Treasury and Downing Street in the run-up to the Budget.

In a letter to the Financial Conduct Authority, Sir Mel wrote: "It seems increasingly clear that the Chancellor has been giving an inaccurate picture of the economic and fiscal context and this appears to be driven by political considerations."

The Shadow Chancellor also claimed "leaks and spin" from the Treasury had led to market speculation being "rife and the gilt markets volatile".

Ms Reeves's Budget fiasco has sparked growing calls for her to resign as Chancellor.

Tory leader Kemi Badenoch this morning claimed the Chancellor should resign for making working Britons cover the costs of her £15billion benefits splurge.

Meanwhile, 51 per cent of Britons believe Ms Reeves will not deliver next year's Budget, having already raised almost £70billion from hiking taxes since entering No11 last year.

However, Ms Reeves insisted she will remain as Chancellor until at least 2027 in a defiant message to Labour MPs ahead of unveiling her £26billion tax raid.