The director-general of the BBC has defended its handling of an allegation that one of its senior presenters paid a teenager for explicit images, after acknowledging that it did not flag a complaint to senior management until a tabloid newspaper approached it.

The broadcaster has been rocked by a report in the tabloid The Sun that the presenter paid a young person 35,000 British pounds ($67,810) for explicit photos over three years, beginning when the person was 17.

The presenter has been suspended but not named, angering other high-profile stars who have fallen under suspicion on social media.

The 100-year-old broadcaster said on Tuesday it had paused its own investigation while the police examine the case. The police said they had requested this to establish whether there was evidence of a criminal offence.

"There remains no police investigation at this time," they said.

According to a timeline published by the broadcaster, a member of the young person's family walked into a BBC building on May 18 to make a complaint.

The family member contacted BBC Audience Services the next day.

The BBC said it made two unsuccessful attempts — one email and one phone call — to respond to the complainant.

The Sun contacted the BBC seven weeks later, on July 6, with different allegations, the broadcaster said on Tuesday, and senior management were informed for the first time.

BBC director-general Tim Davie said: "There was a process of trying to verify the serious complaint … but we had not talked to the presenter until we got the allegations on [July 6], and we talked to them on the day."

Mr Davie, who said he had not personally spoken to the presenter, said the new information provided by The Sun on July 6 "clearly related to potential criminal activity".

"The events of recent days have shown how complex and challenging these kinds of cases can be and how vital it is that they are handled with the utmost diligence and care," he told reporters after the BBC published its annual report.

British Prime Minister Rishi Sunak said the allegations were "very serious and concerning".

'A war between UK's leading publishers'

The saga took a twist on Monday evening, when the BBC said it had been sent a letter from the young person's lawyers stating that the claims in The Sun were "rubbish".

"Nothing inappropriate or unlawful has taken place between our client and the BBC personality," the letter said.

But on Tuesday The Sun doubled down on its story, quoting the mother of the young person, who is now 20, as saying the money from the presenter was used to fuel a crack cocaine addiction.

Media industry publication Press Gazette called the claim and counter-claim "a war between two of the UK's leading news publishers".

Further adding to the stand-off are the slew of attacks on the BBC by members of the ruling Conservative Party and their supporters since the divisive Brexit referendum in 2016.