The Metropolitan Police has told BBC News that the teenage boy at the centre of the Scott Mills sexual offences investigation was under the age of 16.
The sacked BBC Radio 2 DJ, 53, was questioned in 2018 over historical allegations of serious sexual offences. But the investigation, which began in 2016, was closed in 2019 after the Crown Prosecution Service (CPS) deemed there was insufficient evidence to bring charges.
The allegations, first published in the Mirror, are reported to have happened between 1997 and 2000, police said, when Mills would have been in his twenties.
On Monday, it was announced that the former Radio 1 presenter had been sacked by the BBC over allegations related to his personal conduct. The BBC has not given any further details over the allegations and it is not clear what, if any, role the police investigation played in his sacking.
Both Mills and the BBC have been approached for a comment.
BBC News understands that the director general at the time of the police investigation, Tony Hall, did not know about the allegations.
After the sacking was announced, the BBC said in a statement: "While we do not comment on matters relating to individuals, we can confirm Scott Mills is no longer contracted to work with the BBC."
On Tuesday afternoon, Neuroblastoma UK announced it had also decided to "part ways" with Mills, who had been a patron of the children's cancer charity.
"Following his dismissal from the BBC, Neuroblastoma UK have taken the decision to part ways with Scott Mills, and he is no longer a Patron of our charity," they said in a statement.
"We have communicated this decision to Scott and his team, and would like to thank him for his support to date. We remain unwavering in our mission to fund research to find better treatments, and a cure, for neuroblastoma."
Mills has also been an ambassador for the MS Society for the past 11 years. His mum and one of his friends have the condition.
The charity told the Press Association on Monday: "Scott Mills has been an MS Society Ambassador since 2015.
"We are aware of reports regarding his departure from BBC Radio 2, but do not have any further information at this stage."
The BBC has also apologised for not looking into a separate allegation of "inappropriate communications" involving Mills, first reported in the Telegraph, raised by a journalist last year.
The BBC said: "We received a press query in 2025 which included limited information. This should have been followed up and we should have asked further questions. We apologise for this and will look into why this did not happen.
"More broadly, we would always urge anyone who has concerns or information to raise it with us."
Mills' last Radio 2 breakfast show appearance was on Tuesday 24 March, when he signed off by saying: "Back tomorrow."
DJ Gary Davies started the show the following day by saying he was "in for Scott Mills".
Davies and Radio 2's overnight DJ, OJ Borg, will cover the show over the next week, as speculation begins to mount over who will replace Mills on the country's biggest breakfast radio show.
News of the BBC stalwart's departure was first reported by the Mirror, which reported that it "understands the allegation relates to a historic relationship".
A Metropolitan Police spokesperson said in a statement: "In December 2016, the Met began an investigation following a referral from another police force. The investigation related to allegations of serious sexual offences against a teenage boy. These were reported to have taken place between 1997 and 2000.
"As part of these enquiries, a man who was in his 40s at the time of the interview, was questioned by police under caution in July 2018.
"A full file of evidence was submitted to the Crown Prosecution Service, who determined the evidential threshold had not been met to bring charges. Following this advice, the investigation was closed in May 2019."
Mills' former Radio 2 colleague and fellow DJ Jeremy Vine was asked about the sacking on arrival at the BBC's London studios on Tuesday.
"It's a terrible shame," said Vine. "I don't know all the details at the moment so I guess we'll find out.
"It was a shock for all of us yesterday and it happened just before my show, I went on the air so I'm still trying to work it all out."
Former BBC radio presenter Nihal Arthanayake, who was at Radio 1 for more than 10 years at the same time as Mills, told ITV's Good Morning Britain on Tuesday: "My first thoughts were obviously with the alleged victim here, without question.
"But also, Scott Mills is a human, he's a person who got his dream job that has now been taken away from him, and his validation, largely, in life, probably was defined by that job.
"Therefore, we have to be very careful. There's a current feeding frenzy going on.
"A lot of that is driven by people who just hate the BBC, so they'll use that as a stick to beat the BBC with.
"But there is a human being - well, there's two human beings - at the centre of this."
'Come as a shock'
Mills, who took over the breakfast show on Radio 2 from Zoe Ball in January 2025, has worked for the BBC for more than 25 years.
He earned £355,000 - £359,999 in the 12 months leading up until April 2025, according to the latest annual report, making him the corporation's 11th highest-paid star.
His full salary for taking over the breakfast show is almost certainly much higher and is likely to become clear when the next BBC Annual Report is published over the summer.
As one of the corporation's high profile names, his abrupt departure is a fresh blow for the BBC - the last for the current director general Tim Davie, who leaves his role later this week.
It comes after News at Ten presenter Huw Edwards was convicted in 2024 of making indecent images of children, and separately Radio 1 DJ Tim Westwood was charged in October last year with four counts of rape and nine of indecent assault. He will stand trial next year and denies the charges.
Mills joined Radio 2's weekday schedule in 2022 when he replaced Steve Wright as the host of the afternoon slot.
Last year, he provided TV commentary on BBC One for the semi-finals of Eurovision with Rylan. He was last seen on TV in a Traitors skit during Comic Relief.
Prior to his work on Radio 2, Mills was a mainstay on Radio 1 - which he joined in 1998 - for decades.
He became known for his silly but popular and often star-studded features such as Innuendo Bingo, alongside his friend Chris Stark. And also hosted Radio 1's official chart show between 2018 and 2022, replacing Greg James.
Mills - who began his career in local radio at 16, as the country's youngest broadcaster before moving to a new London station, Heart 106.2 in 1995 - hosted a weekend show on BBC Radio 5 Live from 2019 to 2022, and earlier appeared on Strictly Come Dancing in 2014.
In an email sent to staff on Monday morning, Lorna Clarke, director of music at the BBC, said his sacking would "come as a shock".
She said: "Of course, it will also come as a shock to our audience and loyal breakfast show listeners too. I will update everyone with more information on plans for the show when I'm able to."
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