"Henry VIII". Mr Barton told the BBC that he didn't see the original tweet and instead compiled the post after conducting his own research.

This post caught on, and more and more people started talking about Ms Swinson's husband in Facebook groups and on Twitter. Judging from the groups and pages where the story was spread, it's clear that most of the impetus came from Brexiteers - some supporters of the Conservatives or Brexit Party, and others who are left-wing Labour activists.

The online rumours became so strong that the UK branch of Transparency International released a statement in early October.

"Transparency International UK (TI-UK) is independent and politically impartial and does therefore both engage with and objectively criticise politicians regardless of their political opinion or party affiliation," it said. "TI-UKhas neither advocated for or against the UK's continued membership of the European Union.

"TI-UK is not working on any projects funded by the European Union."

The story continues to spread

But that press release did not stop the story from spreading and morphing. It exploded into the mainstream when it was shared by Leave.EU, a pro-Brexit Facebook page with almost a million followers. This post was shared 18,000 times and received thousands of likes and comments:

It got even further traction over the next few days when it was written up by politically themed Facebook pages with big followings that purport to post news stories.

One called "Unity News Network", which was set up by pro-Brexit activists, put up a post broadly similar to the examples above. The post linked to an