What was claimed
Sir Keir Starmer has legalised marriage between brothers and sisters or parents and their children.
Our verdict
False. Marriage between close relatives is illegal in the UK.
No, the government hasn’t legalised marriage between brothers and sisters and parents and children
Viral posts being shared on social media falsely claim that Prime Minister Sir Keir Starmer has legalised incest in the UK at the request of the Muslim community.
One post on X, which has been viewed more than 800,000 times, says: “WOW!!! Cant make this up!!!! INCEST LEGALIZED. At the request of the Muslim lobby, Keir Starmer legalized in the United Kingdom marriages between brothers and sisters, fathers and daughters, sons, and mothers.”
The post then quotes from a supposed exchange in Parliament in which “one of the deputies” allegedly says to the Prime Minister: “Mr Starmer, do you understand what you are doing? You are legalizing marriages between brothers and sisters, between parents and children.
“This carries catastrophic health risks for people, many of which can not be determined until the child is born. If this practice continues from generation to generation, the English people will disappear.”
According to the post, Mr Starmer then replied: “Yes. I have already stated my position.”
The post is accompanied by footage from the House of Commons, but the words that were actually spoken do not match those in the post. The filmed exchange is from 5 March 2025 and shows Conservative MP Richard Holden asking Mr Starmer whether he will support his Bill—the Marriage (Prohibited Degrees of Relationship Bill)—to ban marriage between first cousins.
Instead of the answer quoted in the post, the footage shows Mr Starmer actually saying: “Mr Speaker, we have taken our position on that Bill.”
Similar posts have also been shared many times on Facebook.
While marriages between first cousins are currently legal in the UK, there are concerns about potential health risks if the marriage results in children, as the couple shares the same set of grandparents.
Marriages to a sibling, parent, child or other specific relatives are prohibited under the Marriage Act 1949, while sexual activity between close relatives is a criminal offence under the Sexual Offences Act 2003. There is no evidence that Mr Starmer or the government have any plans to change either law in any way.
It’s important to consider whether information you see on social media comes from a trustworthy and verifiable source before sharing it. Our toolkit provides some advice about how to do this.
This article is part of our work fact checking potentially false pictures, videos and stories on Facebook. You can read more about this—and find out how to report Facebook content—here. For the purposes of that scheme, we’ve rated this claim as false because marriage between close relatives remains illegal in the UK.