Explosive new claims that Lloyds wrecked small businesses for a profit during the financial crisis are being probed by regulators.

Bankers conspired to tip firms into administration by loading them with fees they could never pay, says a whistleblower's testimony seen by the Mail.

These companies' assets were then seized by Lloyds and partner companies to boost profits, says the insider – a subcontractor involved in rescuing firms.

New allegations: Lloyds bankers are accused of conspiring to tip firms into administration by loading them with fees they could never pay

Rumours have long swirled that big banks destroyed companies in the wake of the financial crisis to confiscate property and shore up their own balance sheets – claims the lenders deny.

But this is the first time an insider involved in the process has spoken out about what went on.

The whistleblower has now been interviewed for more than an hour by the Financial Conduct Authority (FCA), and its chief executive Andrew Bailey is understood to be aware of the claims.

Evidence has also been shared with the National Crime Agency, the Mail understands.

Toxic Treasury probe Claims the Treasury was closely involved in a toxic banking unit must be investigated by MPs, Liberal Democrat leader Sir Vince Cable has said. It is alleged the Asset Protection Agency – part of the Treasury – instructed Royal Bank of Scotland's infamous global restructuring group about lending decisions after the lender's £46billion bailout by taxpayers.

The whistleblower claims that a turnaround business called Baronsmead conspired with Lloyds to push firms into administration even when they could be saved.

In previously unpublished court documents, the insider – who was supported by campaign group Whisleblowers UK – sets out how Baronsmead was appointed in 2012 by struggling property company Angel Group to help save it from collapse, and paid £3,500 a day for its efforts.

But the insider claims that from the start, Baronsmead was conspiring to wreck the company.

When the whistleblower raised concerns, they claim, Baronsmead's boss Ian Gray said: 'You should remember who your paymaster is, and not to upset Lloyds with difficult questions.'

The insider said: 'Lloyds had an agenda to place the companies into administration no matter.'

The whistleblower's claims were made during a court battle between Lloyds and Julie Davey, the owner of Angel and one of Britain's wealthiest women before the financial crisis due to her property empire.

She lost the case and was reprimanded by the judge for misleading the court but the whistleblower's evidence was not criticised.

Lloyds has paid £100million in compensation after criminal bankers at the Reading branch of HBOS, which it rescued in 2008 seized companies' assets.

Gray said: 'There is no truth whatsoever in any of the allegations that Julie Davey or anyone else is making of wrongdoing by myself or Baronsmead.'

Lloyds said: 'The allegation of a conspiracy is long-standing and has been investigated fully by the bank, including the information provided by [the whistleblower].

This allegation is categorically denied.' It is understood the whistleblower did not go to Lloyds with their concerns.

The FCA declined to comment.