Downing Street has described the sexual assault allegations made against Russell Brand by four different women as “very serious and concerning”.

The 48-year-old comedian and actor has been accused of rape, assault and emotional abuse between 2006 and 2013, when he was at the height of his fame working for the BBC, Channel 4 and starring in Hollywood films.

Brand vehemently denies the allegations, which also include claims of controlling, abusive and predatory behaviour, and said, in a video posted online on Friday night, that all of his relationships have been “consensual”.

Prime Minister Rishi Sunak’s official spokesman said: “These are very serious and concerning allegations.

“The Met Police has asked anyone who believes they have been a victim of a sexual assault to come forward to speak to officers.

“As the Foreign Secretary said over the weekend, people should feel able to raise concerns where they have them and know they will be treated seriously and treated with sensitivity.

“The Prime Minister has been clear there should never be any space for harassment, regardless of where it is found.”

The BBC, Channel 4 and Banijay UK, which bought Endemol, the company commissioned by Channel 4 to produce the Big Brother spin-off shows Brand hosted, have all launched investigations into Brand’s behaviour while he was working on their programmes.

Downing Street urged the BBC and Channel 4 to set out the results of their investigations into Brand “transparently”.

The No 10 spokesman said: “It’s right that this is looked into and I think both of the broadcasters have said they would investigate, and that is the right step.

“I’m not going to prejudge that, it will be for them to set out what they find and do so transparently.”

Culture Secretary Lucy Frazer is expected to speak to broadcasters about their investigations into Brand at the first available opportunity.

It is understood she will seek assurances that their inquiries will be carried out thoroughly and transparently.

In recent years Brand has forged a new path as a wellness influencer and host of a YouTube show but Downing Street declined to urge broadcasters and streaming platforms such as YouTube and Netflix to take down his output.

The Prime Minister’s official spokesman said: “It’s a decision for all broadcasters to consider the right approach in light of these very serious allegations. They are deeply concerning, they need to be investigated.

“But I’m not going to dictate the actions of broadcasters or streaming services.”

The allegations, detailed in a joint investigation by the Times, Sunday Times and Channel 4’s Dispatches, include one woman who says she was sexually assaulted during a three-month relationship with Brand when she was 16 and still at school.

The woman described his behaviour towards her as “grooming” as he would allegedly provide her with scripts on how to deceive her parents into allowing her to visit him.

The BBC is facing questions after she claimed that he used the corporation’s car service to pick her up from school to take her to his home.

The broadcaster previously said it is “urgently looking into the issues raised” while Brand worked on BBC radio programmes between 2006 and 2008.

In 2020, the same woman contacted contacted Brand’s literary agent at the time, who was also the co-founder of talent agency Tavistock Wood.

A spokesman for the agency said Brand “categorically and vehemently denied the allegations” at the time but they now believe they were “horribly misled” and have terminated all professional ties with the comedian.

Another woman has said she was raped against a wall at Brand’s home in Los Angeles.

Channel 4 announced it is carrying out “its own internal investigation” following the allegations and the broadcaster has removed content featuring Brand from its streaming service while it looks into the claims.

“We will be writing to all our current suppliers reminding them of their responsibilities under our Code of Conduct, as we are committed to ensuring our industry has safe, inclusive and professional working environments,” a Channel 4 statement added.

It comes after Brand was accused of pursuing audience members for sex while presenting Big Brother spin-off shows EFourum and Big Brother’s Big Mouth on Channel 4.

A researcher claimed concerns about Brand’s behaviour were reported to production managers at Endemol, the company commissioned by Channel 4 to produce the programmes in 2004 and 2005, but were dismissed.

Banijay UK, which bought Endemol in 2020, later announced it has launched an “urgent internal investigation” and encouraged “anybody who feels that they were affected by Brand’s behaviour” to come forward.

The Metropolitan Police said they will speak to The Sunday Times and Channel 4 to ensure “any victims of crime who they have spoken with are aware of how they may report any criminal allegations to police”.

A spokesman for the Los Angeles Police Department (LAPD) told the PA news agency they do not have an open investigation into Brand, and another confirmed there have been no arrests following two allegations concerning claims that are said to have happened in the US.

Meanwhile, questions are now being asked about whether TV chiefs were aware of any concerns about Brand’s behaviour while working on their programmes.

Caroline Dineage, chairwoman of the Commons Culture, Media, and Sport Committee, told Times Radio there may be a “full-on inquiry” into the culture of “open secrets” in the TV industry and behaviour of media “giants”.

She said TV executives could be invited to give evidence in front of the select committee, adding: “We’re going to be writing to the TV companies and asking them to set out the process for the inquiries that they’re making, and we need a kind of sense of timelines on this.

“But we’re not ruling out inviting them in to give evidence to the select committee if we don’t feel that we’re getting a satisfactory response.”

In a video statement posted online ahead of the publication of the claims, Brand said he was facing a “litany of extremely egregious and aggressive attacks”.

“Amidst this litany of astonishing, rather baroque attacks are some very serious allegations that I absolutely refute,” he said.

As Dispatches aired on Saturday evening, Brand performed a sold-out comedy gig at the Troubadour Wembley Park Theatre in north-west London as part of his Russell Brand Bipolarisation tour.

He is scheduled to perform at three more venues in September, including a show at the Theatre Royal in Windsor on Tuesday, The Pavilions in Plymouth on Friday, and The Civic At The Halls in Wolverhampton next Thursday.