Warning: contains details of alleged sexual offences and misconduct
The Metropolitan Police are encouraging "anyone who believes they have been a victim of sexual assault" after participating on Channel 4's Married At First Sight UK to contact them.
A BBC Panorama investigation revealed allegations that two women had been raped during filming on the reality TV show, while a third said she had been the victim of a non-consensual sex act.
The Met is also believed to be approaching Channel 4 for more information.
The prime minister's official spokesperson earlier called the claims "extremely serious" and said they must be investigated.
A Met spokesperson said the force had not received any criminal reports in relation to the matter.
They said: "We continue to encourage anyone who believes they have been a victim of sexual assault, no matter how long ago it happened, to get in touch with us."
The force said it was approaching production teams involved in the reality TV show to "ensure anyone they have spoken to is aware of how to report any criminal allegations".
Since the broadcast of the Panorama investigation, Channel 4 has faced questions over the claims made about the hit show.
Regulator Ofcom said broadcasters needed to take "due care" over the welfare of show participants.
Holiday company Tui told BBC News it was pausing sponsorship of the show.
Channel 4 has now removed all episodes of the programme from its streaming and linear services, alongside MAFS UK social channels.
In a statement released shortly after BBC News broke the story on Monday, Channel 4 said it had commissioned an external review of welfare on the show last month "after being presented with serious allegations of wrongdoing".
Lawyers for CPL, an independent production company which makes the UK version of the show, said its welfare system was "gold standard" and industry-leading, and that it had acted appropriately in all these cases.
Channel 4's chief executive Priya Dogra expressed sympathy to contributors who had "clearly been distressed after taking part in Married at First Sight".
She said the allegations were disputed by those accused, adding that she believed the broadcaster had "acted quickly, appropriately, sensitively and with well-being front and centre" when concerns were raised.
However, when asked by a reporter if she wanted to apologise to the women involved, she declined to comment and walked off back into Channel 4's London headquarters.
On Tuesday, the prime minister's spokesperson said: "These are extremely concerning and serious allegations.
"It's right that Channel 4 has commissioned an external review and that all allegations are referred to the appropriate authorities and investigated with the full co-operation of those involved.
"Where wrongdoing or criminality is found there must be consequences and appropriate action taken to ensure it can never happen again."
Since the Panorama investigation went out last night, BBC News has been contacted directly by a number of former Married at First Sight UK cast members, who are raising concerns.
Social media has also lit up, with former cast members expressing their support for the women who have spoken out, and calling for action. But others have said their experiences were positive.
Earlier, security minister Dan Jarvis said he was "extremely concerned" about the allegations raised in the BBC investigation and called on Channel 4 and CPL to fully investigate them.
"I would also say given the very serious nature of these allegations, I think it's highly likely that there will be a referral to the police and it will be a police matter for them to investigate," he added.
Alex Mahon, who was chief executive of Channel 4 from 2017 to 2025, faced questions from MPs in a pre-scheduled meeting of the Culture, Media and Sport Committee on Tuesday.
"I watched the programme and there were some very serious and concerning allegations in it."
Referring to the review announced by Channel 4, she said: "I think the right thing for them to do is to launch an investigation... and then we should see what those investigations come up with and act on the findings."
Speaking about whether more needed to be done, she told the committee: "The industry is always trying to evolve and take allegations or incidents very seriously.
"The duty of care protocols, therefore, do advance all the time but it's always worth another look, especially in this case as they are quite serious allegations, to make sure enough was done and enough is being done, and that protocols are evolving in the appropriate way."
The chair of the committee, Caroline Dinenage, told BBC News that MAFS UK did "involve an element of risk" as a show.
"It's a TV show that almost expects and anticipates people that have only just met will have to become really quite intimate with each other," she said.
"They're expected to share a bed and a life together within minutes of meeting - it almost feels like an accident waiting to happen."
She told BBC Radio 4's Today programme that MAFS needed to have made sure protections were in place before, during and after filming because the women in the Panorama documentary "didn't realise fully what had happened to them until afterwards".
Billed as a "bold social experiment", MAFS sees single people agree to "marry" total strangers, after meeting for the first time at their mock weddings.
The three women making the allegations all say Channel 4 did not do enough to protect them.
Channel 4 was aware of some allegations before broadcast, and all the episodes featuring the women had been available on its streaming service before they were removed on Monday.
Channel 4 had previously told Panorama that all the allegations were wholly uncorroborated and disputed.
The "marriages" in the show are not legally binding, but viewers see the couples go on a "honeymoon", before moving in together and navigating their relationships - all while being filmed, almost every day.
The three women we have spoken to are all making allegations about the men they were partnered with and said that they are speaking to the BBC because they felt they should have been better protected.
One said she wanted CPL to stop "allowing harm to come to people".
Lawyers for the first woman's onscreen husband said he denied rape and said that all sexual contact had been entirely consensual. He also denied being violent towards her or making violent threats to her, they said.
Lawyers for the second woman's onscreen husband said he had challenged details of her account. They said the sex had started consensually but that she had communicated through her body language that she was no longer consenting and he had then stopped immediately.
Skelly said he had understood Manderson had consented to him ejaculating inside her that night. In a statement he said he categorically denied "any allegations of sexual misconduct" or that he was "controlling".
Their relationship "was based on mutual consent, care and affection", he said.
Meanwhile, the Film and TV Charity, which assists workers in the industry, posted a message of support for those who may have been affected by Monday's Panorama.
MAFS is a highly successful global TV franchise. Many couples say they enter the show with the aim of finding love. Others are seeking social media fame.
The UK version, which has been running for 10 seasons, is broadcast at prime time on Channel 4's sister channel E4. All episodes had been available on the streaming service All4.
Audience figures often top three million, making the show one of the jewels in Channel 4's crown.
It is understood no decision has been made on the broadcast of MAFS UK series 6.
Former safeguarding minister Jess Phillips told BBC News after watching Panorama it felt "so likely" that issues like this might arise on the show.
"The production should have had specialists in domestic abuse and sexual violence on hand to advise," she said.
"Literally any sign of trouble such as this should have been met with immediate plug pulling, not putting it on the victim to make that decision when she feels beholden."
Farah Nazeer, chief executive of charity Women's Aid, told the BBC: "The moment that some of those issues were raised, they should have been really proactive with safeguarding.
"Anyone who has experienced that kind of abuse takes time to really be able to share - there's a lot of trauma involved, there's a lot of, often times, shame involved."
Nazeer said everyone involved in reality TV shows needed to be trained on how to safeguard against domestic abuse and assault, adding that independent organisations not paid by the production company should be involved.
"If broadcasters are going to make programmes centred on intimacy, they have to equally centre safeguarding and care," she said.
"I think what the stories reveal is that in those instances where those women raised flags talking about bruising, assault and so on - really serious issues - they were not pulled immediately from those relationships."
A DCMS spokesperson told BBC News: "All allegations must be referred to the appropriate authorities and investigated with the full co-operation of those involved, with action taken to ensure that the highest standards are upheld and there are consequences for criminality or wrongdoing."
An Ofcom spokesperson said: "Under our rules, broadcasters are required to take due care over the welfare of people who might be at risk of significant harm as a result of taking part in a programme."
"We note that Channel 4 has launched an external review into contributor care on MAFS UK and we await its findings," they added. "We will review this and all other evidence made available to us."
If you are affected by any of the issues in this story, help and support is available at BBC Action Line.
Correction: An earlier version of this story said Tui was stopping its sponsorship of the show. This has been changed to say it is pausing its sponsorship.
