The Prime Minister said a review into how failed firm Greensill Capital was able to secure Government contracts will be given the “maximum possible access” to get to the bottom of what happened.

Downing Street announced on Monday that senior lawyer, Nigel Boardman, has been commissioned to carry out a probe into how the specialist bank – founded by Australian financier Lex Greensill – was granted access to a Covid loan scheme for businesses, putting hundreds of millions of pounds taxpayers’ money at risk.

The firm later collapsed into administration but not before former prime minister David Cameron unsuccessfully lobbied ministers on its behalf in a bid to ask for support for Greensill through the Government’s Covid Corporate Financing Facility (CCFF).

Boris Johnson told broadcasters on Tuesday: “I’ve asked Nigel Boardman to have a look at this whole issue of supply chain finance and given him pretty much carte blanche to ask anybody whatever he needs to find out.

“I would like it to be done quickly, but I want him to have the maximum possible access so we can all understand exactly what has happened, and that will of course be presented to Parliament in due course.”

Mr Johnson said it was for Mr Boardman to judge on his predecessor Mr Cameron’s behaviour.

Mr Cameron sent a number of texts to Mr Sunak’s private phone when bidding for CCFF support for Greensill.

It was later reported that Mr Cameron had arranged a “private drink” between Health Secretary Matt Hancock and Mr Greensill to discuss a payment scheme later rolled out in the NHS.

The former Conservative leader also emailed a senior Downing Street adviser, pressing for a rethink on Mr Greensill’s application for access to emergency funding.

Mr Johnson was pressed on whether he was looking to “rough up a rival” via the review given the long history between him and Mr Cameron.

The Prime Minister replied: “I think people have got questions that they need to satisfy themselves about – including me – about how this supply chain finance stuff is meant to work.

“I don’t think it is going on at present anywhere in Government, but we need to understand exactly what the intention was, how it came about, and that is exactly what Nigel Boardman is going to do.”

Shadow chancellor Anneliese Dodds has been granted an urgent Commons question calling on Chancellor Rishi Sunak to explain his involvement with the Greensill affair.

The wording of the question means business minister Paul Scully will respond for the Government, as officials say Greensill was chosen as a lender by the British Business Bank, which is overseen by the Department for Business, Energy and Industrial Strategy.