British cryptocurrency investor and billionaire Christopher Harborne made headlines when it was revealed he gave £5million to Reform Party leader Nigel Farage before he was an MP.

Last year Harborne also gave a single donation of £9m to Reform UK - the biggest ever donation to a UK political party by a living person. He has also previously donated to the Brexit Party and the Conservatives.

Very little is known about the Cambridge-educated businessman, who is also known as Chakrit Sakunkrit.

So how did he make his fortune? And why is he so interested in British politics when he has lived abroad for the last few decades?

Mark Coles talks to journalists Tom Burgis and Ceri Thomas, and family friend Mark Vellacott, to paint a picture of one of the most powerful men funding British politics.

Presenter: Mark Coles