A top mandarin is to be grilled over text messages sent by David Cameron as committee chairs are in talks about launching an inquiry into Greensill.
Sir Tom Scholar, Permanent Secretary at The Treasury, will appear before the Public Accounts Committee on April 22, where he will be asked questions about Greensill, a finance firm advised by the former prime minister which sought access to government coronavirus support funding.
The Telegraph understands that discussions are underway along Parliament’s select committee corridor about a bigger inquiry, with two senior members of committees currently working closely together so as not to “overlap” witnesses.
One senior Tory MP said the Cabinet Secretary, Simon Case, is due to come before the Public Administration and Constitutional Affairs Committee "in the next couple of weeks". He said while it would be a "routine appearance" he was "sure Greensill will be a feature of it".
It comes after further revelations regarding the lobbying row over the collapsed lender found the Health Secretary, Matt Hancock, met Mr Cameron and Lex Greensill for a "private drink" to discuss a new payment scheme for the NHS in 2019, according to The Sunday Times.
Mr Greensill's firm at the time wanted to introduce a flexible scheme to pay doctors and nurses either daily or weekly.
NHS SBS, a joint venture between the Department of Health and Social Care (DHSC) and a French IT firm, went on to announce in October last year that Earnd, a mobile app that was then a division of Greensill, would be available free-of-charge to NHS employees to access their pay.
Mr Hancock referred Mr Greensill to work directly with the NHS rather than his department, according to an ally of his, who insisted the final decision to use the scheme was for local NHS employers.
"Matt acted in entirely the correct way - he updated officials on the business that was discussed, as is appropriate," the friend said.
Mr Hancock is the fourth minister to have been lobbied by Mr Cameron on behalf of the company, with Rishi Sunak and Treasury ministers Jesse Norman and John Glen also having been contacted by him.
It was also revealed that the Treasury reconsidered Mr Greensill's application for an emergency coronavirus loan after Mr Cameron messaged a senior adviser to Boris Johnson.
Mr Cameron was said to have described the decision to exclude his employer's firm, Greensill Capital, from the multibillion-pound scheme as "nuts" and pressed for the Chancellor to reconsider.
On April 3 last year Mr Cameron emailed: "What we need is for Rishi (Sunak) to have a good look at this and ask officials to find a way of making it work.”
Sir Alistair Graham, a former chairman of the committee on standards in public life, told Sky News the lobbying raised “big questions” about "ministers who leave office who get very well paid jobs in the private sector that could almost be seen an extension to their pension arrangements."
He added: “I think there are important lessons to learn and new rules may be required".
While Mr Cameron has not commented publicly on the allegations, a source close to him said: "David Cameron was an enthusiastic champion of Greensill's pay product, Earnd, and met with various people to discuss its rollout across the NHS."
Meg Hillier, chairwoman of the Public Accounts Committee, told The Telegraph that there are “many questions about Greensill's access to Government”.
She said: “The Government had to act fast at the beginning of the pandemic but it had no licence to act fast and loose.
"Too often, as the PAC and NAO have highlighted, basic checks were not carried out. And transparency over decisions made- particularly in awarding contracts has been poor. We need to know why and how Greensill secured what seems to be preferential access to cabinet ministers, officials and schemes.
“The fact that information is only dripping out shows a woeful attitude to transparency about how Greensill got this access.”
A DHSC spokesman said: "Our approach was and is that local NHS employers are best placed to decide how different pay flexibilities fit with their overall pay and reward offer for their staff."
A No 10 spokesman: "Throughout the pandemic, an immense number of businesses contacted Downing Street with representations; these were passed on to relevant departments."