A spokesman for 10 Downing Street denies the allegations, telling Fortune that “any suggestion of a cover-up is completely untrue,” but declined to answer why the information was only emerging now, a year after requests were made under the Freedom of Information Act.

The allegations date back to 2015, when Johnson was trying to introduce new regulations to slow the explosive growth in private-hire cars in London, concerned by their effect on traffic congestion, air quality, illegal parking, and other issues. The Daily Mail report that, at the time, police were receiving reports of rape or assault tied to Uber drivers at a rate of one every 11 days.

The Mail and Financial Times say that Cameron and his then-Treasury chief, George Osborne, had both leaned on Johnson to withdraw a new regulation imposing a minimum five-minute waiting time on people booking cabs, so as to deter Uber drivers from circling popular pick-up points. Johnson withdrew most of the proposals in January 2016.

Asked last year about the allegations, 10 Downing Street had said there had been no contact between it and City Hall on the subject. However, the Mail says Transport for London, the body that runs public transport and regulates the taxi industry in the U.K. capital, had released e-mails showing that Daniel Korski, then deputy head of Cameron’s policy unit, had had extensive e-mail contact with City Hall about the regulation, pressuring it to water down the new rules. The Mail said Korski had been told to ensure that Johnson didn’t upset Uber.

As in many cities, Uber’s ride-hailing model has been resisted by licensed cab drivers, who say Uber’s drivers compete unfairly by being able to get around regulations on regular taxis.

It’s quite possible that Cameron and Osborne, from the traditionally pro-competition Conservative Party, were motivated chiefly by policy considerations. Uber pointed out in an e-mailed statement that “More than 200,000 Londoners signed a petition in autumn 2015 against plans for things like five-minute minimum waiting times. They were also condemned by consumer groups, the media, and even the Competition and Markets Authority.”

All the same, drivers of London’s black cabs say they suspect Uber of using back-channel contacts to get the regulations watered down.

Steve McNamara of the Licensed Taxi Drivers’ Association accused Downing Street of acting “like paid-up lobbyists for Uber.”

“They leaned on Boris and Transport for London, and ended up getting exactly what they wanted. It’s a disgrace, a scandal,” McNamara told the Mail.

Uber’s Rachel Whetstone, a senior VP for communications, is married to Cameron’s former policy guru Steve Hilton. The couple were godparents to the Camerons’ late eldest child, Ivan. In addition, the Mail noted that Uber’s senior public policy analyst in Europe, Guy Levin, was formerly an adviser to Osborne while the latter ran the Treasury. Uber didn’t answer a question from Fortune whether there were internal procedures to stop Whetstone from using her personal connections to Cameron.

Both Cameron and Osborne resigned last year after failing to persuade the U.K. to stay in the EU. Osborne has since taken a well-paid advisory role with Blackrock, which invested some $150 million in an Uber funding round in 2014.

Neither McNamara nor Uber responded immediately to a request for comment from Fortune Tuesday.