Housing Secretary Robert Jenrick texted the businessman behind a controversial planning application in November while preparing to decide whether to approve it, newly published documents show.
Messages released by Mr Jenrick show he told Richard Desmond he hoped to see him soon, after sitting next to him at a dinner the night before.
Labour said it showed “discrepancies” in Mr Jenrick’s account of events.
But Downing Street said Boris Johnson now considered the matter “closed”.
Amid calls from opposition MPs for a full inquiry by the cabinet secretary, the UK’s top civil servant Sir Mark Sedwill said Mr Jenrick had given a “full and factual account” of his actions.
Mr Jenrick released the papers to hit back at Labour allegations of “cash for favours” in relation to his approval of a massive housing development on the site of the former Westferry Print Works in east London.
Mr Desmond made a personal donation of £12,000 to the Conservative Party 12 days after the minister overruled government planning inspectors to approve the development, in January.
Mr Jenrick’s decision to approve the development was later challenged by Tower Hamlets Council, forcing the secretary of state to say what he did was “unlawful by reason of apparent bias”. It is now being handled by another minister.
Mr Jenrick insists he had no knowledge of Mr Desmond’s donation and that his decision to overrule the inspectors was “not unusual” and motivated by a desire to see more homes built.
The documents include personal correspondence between the minister and Mr Desmond, owner of property developers Northern & Shell, in the run-up to the decision on 14 January.
They show that in the aftermath of a fundraising dinner on 18 November, in which Mr Jenrick sat next to the businessman, Mr Desmond requested a meeting with the minister and suggested he visit the site on the Isle of Dogs.
Mr Jenrick asked a member of his staff to arrange it, emails show. However the next day Mr Jenrick said by text that they shouldn’t meet again to avoid “any appearance of being influenced”.
The arranged meeting appears to have been cancelled nearly a month later because Mr Jenrick had to be in Parliament for the Queen’s Speech.
Mr Desmond, the former owner of Express newspapers, had been lobbying for the proposed 1,500-home development to be approved before the local council, Tower Hamlets, introduced a levy to pay for local services.
Mr Desmond sent a text to Mr Jenrick saying, in apparent reference to Tower Hamlets’ Labour council, “we don’t want to give Marxists loads of doe (sic) for nothing”.
Internal emails from the Ministry of Housing suggest Mr Jenrick was “flagging” the project with his officials, warning them there was “sensitivity with timing”, and asking them to advise him before Christmas.
In one document, a civil servant said the secretary of state wanted the development signed off the following day, adding “on timing, my understanding is that SoS is/was insistent that decision issued this week ie tomorrow – as next week the viability of the scheme is impacted by a change in the London CIL [a planning charge] regime”.
The documents released make clear that Mr Jenrick supported the housing project, in the face of opposition from his officials.
Mr Jenrick also released a letter to the chair of the housing communities and local government select committee revealing that he informed civil servants of the dinner with Mr Desmond a month later, in December.
He wrote: “On my first full day in office after my re-appointment, I told my private office I had met Mr Desmond for dinner, that he had raised the application and that I said I could not discuss,”
Labour said the “explosive revelations” suggested Mr Jenrick “rushed through” the application so that Mr Desmond’s company could avoid the levy.
The opposition says Mr Jenrick also overruled his advisers to reduce the amount of affordable housing required in the development, potentially saving Mr Desmond a further £106m.
“The documents clearly show that Mr Jenrick did not notify officials immediately after his meeting with Mr Desmond,” shadow communities secretary Steve Reed said. “Rather than ‘closing down’ the discussion as he claims, he initiated contact with Mr Desmond by text message the following day.”
He said he was “far from satisfied” with Mr Jenrick’s answers, claiming the text exchanges with Mr Desmond were “highly inappropriate” and “not in the spirit of the ministerial code of conduct”.
“The housing secretary needs to explain these discrepancies as a matter of urgency: the public must be reassured that there is not one rule for the Conservatives and their wealthy donors and another rule for everyone else,” he added.
Speaking in the Commons before the documents were released, Mr Jenrick said the accusations were “not simply wrong but actually outrageous”, adding that the decision had been made on its merits after a thorough process, but he admitted “things could and should have been done differently”.
“On reflection, I should have handled the communication differently,” he said.
Conservative backbencher Bernard Jenkin backed Mr Jenrick to stay in his job and told BBC Radio 4’s Today programme that while there had been a mistake there was “no sign of actual maladministration”.
Tower Hamlets councillors asked the High Court in April to order the government to disclose emails and memos around the deal.
Rather than doing this, Mr Jenrick’s lawyers conceded the timing of his decision “would lead the fair-minded and informed observer to conclude that there was a real possibility” that he had been biased.
Mr Desmond told The Sunday Times last weekend that he had shown Mr Jenrick a promotional video for the scheme on his mobile phone during the fundraiser at the Savoy Hotel.
When pressed by the SNP’s communities spokesman David Linden about Mr Desmond’s claims, Mr Jenrick said: “He did bring out his iPhone and showed me some images of the development.”
But the minister said he had told Mr Desmond “it was not appropriate to discuss the matter and I couldn’t comment on it”.