After a number of lapsed deadlines to provide the report, the government-owned business was told by the Business and Trade Committee chair it had a deadline of 9am on Tuesday morning.

If it was not submitted by then, the committee warned it would discuss formally summoning the document, an infrequently used and limited power retained by MP committees when they are unsuccessful in their normal requests.

It has not been disclosed if the deadline was met.

But a Post Office spokesperson said: "We can confirm our senior independent director on the board, Ben Tidswell, has written to the Business and Trade Select Committee this morning regarding their request for a document."

The existence of the report came as a bombshell last week.

It had been thought that the former Post Office chairman Henry Staunton, sacked earlier this year by business secretary Kemi Badenoch, had been subject to investigation.

But at the committee hearing last week, Mr Staunton said he was only mentioned in one paragraph and the report was "a big investigation into Nick".

The report was compiled by a former human resources (HR) director and whistle-blower and said Mr Read threatened to resign because he was unhappy with his pay and made accusations of bullying. According to a Sunday Times report, Mr Read sought a £1.1m pay package.

Mr Read has denied he made resignation threats.

Sub-postmaster victims of the Post Office's faulty Horizon software have been seeking redress after hundreds were convicted of false accounting, theft and fraud and many more lost their businesses and were in financial and personal ruin after the Fujitsu-built accounting software wrongfully documented monetary shortfalls.

The postmasters' fight for justice had been increasingly overshadowed by corporate wrangling of the Post Office.

Read more:
Who is Henry Staunton, the City grandee who took on Kemi Badenoch?

After he was removed from his post, Mr Staunton said he had been told by the Department for Business and Trade to slow down the processing of compensation.

In documents exclusively obtained by Sky News, he called for the Post Office to be "removed completely" from the compensation process and for it to be put under the control of postmasters due to the "deep dysfunction" within the organisation.

It's understood the chair of the Business and Trade Committee, Labour MP Liam Byrne, requested the HR investigation be sent to the committee by last Thursday, and when the deadline passed, by Monday afternoon.