Mr Justice Holgate ruled last month that housing secretary Robert Jenrick's decision to grant permission for the redevelopment of the former Daily Express printworks at Westferry must be redetermined.
The secretary of state permitted the 1,524-home application, which had been submitted by an offshoot of the Daily Express' former parent company Northern & Shell, even though his inspector David Prentis had recommended refusal.
Consenting to judgment in the case, the secretary of state admitted that the decision letter had been issued on the day before local planning authority the London Borough of Tower Hamlets was due to adopt its new local plan and Community Infrastructure Levy (CIL) charging schedule.
Under the new schedule, Tower Hamlets estimated that the developer would have had to pay up to £50 million more to the council.
In the consent order, the secretary of state "explained that the [decision letter] was issued on 14 January 2020 so that it would be issued before the claimant adopted its new local plan and CIL charging schedule".
Jenrick accepted in the order that the timing of the letter meant that the decision letter was "unlawful by reason of apparent bias".
In a letter to Cabinet chief secretary Sir Mark Sedwill, Labour's shadow housing and planning minister Mike Amesbury, has called for a full investigation of the matter by the Cabinet Office.
He wrote: "The consequence of Mr Jenrick's decision was to save a developer a very great amount of money and, in the light of conceding the judicial review claim give rise to serious questions which require answers."
Specifically, Amesbury asked for details on contacts between Jenrick or officials in his department and the developer or their representatives regarding the application and, specifically the CIL liabilities.
He also asked if Jenrick had spoken with Prime Minister Boris Johnson regarding the application and called on the Cabinet Office to ensure that the secretary of state releases the documents to allow full public scrutiny to take place.
Amesbury further asked why Jenrick went against his inspector's recommendation to refuse the application and how Tower Hamlets Council can trust the decision when it is taken again by a different cabinet member.
In a statement, he added: "Serious questions need to be answered about why this decision was taken, a decision which could have saved a Conservative donor tens of millions of pounds, and in the process deprived local residents of vital infrastructure funding.
"It's essential that we have transparency in processes such as this so that trust can be maintained in our housing and planning system.
"I hope the Cabinet Office will uphold this spirit of transparency, do the right thing and conduct a thorough investigation into the events around this decision."
Planning has asked the Ministry of Housing, Communities and Local Government (MHCLG) for a comment but had not received one by time of publication.
In a previous statement, the MHCLG has said: “While we reject the suggestion that there was any actual bias in the decision, we have agreed that the application will be redetermined."
Yesterday, the Mail on Sunday reported that Jenrick had attended a Conservative Party fundraising dinner with Northern and Shell owner Richard Desmond, who the newspaper said had raised the topic of the application with him.
According to a statement submitted by Jenrick's spokesperson to the Mail on Sunday, the secretary of state told Desmond at the dinner that discussing the application would be inappropriate.
The paper quoted the spokesperson saying: "They were put on the same table, although Mr Jenrick was not aware of this prior to arriving at the venue.
"The developers did raise their application, but Mr Jenrick informed them that it would not be appropriate for them to discuss the matter with him, or for him to pass comment on it."