A mummy discovered in a Swiss church is an ancestor of British Foreign Secretary Boris Johnson, scientists have determined.

Anna Catharina Bischoff is believed to be the great-great-great-great-great-great-grandmother of the British Foreign Secretary.

The 230-year-old unknown mummy was discovered four decades ago during excavations of Barfusser church in Basel.

Anthropologist Gerhard Hotz, curator at Basel's Natural History Museum, said identifying her took two years of thorough research, having started with almost no information on who the mummy was.

He told the Press Association: "It is quite significant because nobody ever has done such a thing. We didn't know anything."

A trawl of ancestral archives allowed researchers to identify the grave number and name of the mummy at the church, where there were 110 plots.

They then extracted DNA from the mummy's toe which gave a 99.8% match to two living descendants - living in Basel and Ohio, Dr Hotz said.

Ms Bischoff died in Basel in 1787 aged 68.

Her daughter married Christian Friedrich Pfeffel von Kriegelstein, Dr Hotz said, making her an ancestor of Mr Johnson, whose full name is Alexander Boris de Pfeffel Johnson.

Dr Hotz spoke of his pride in the project, which involved a team of more than 40 people, adding that discovering the link to Mr Johnson was the icing on the cake.

He said: "It was a risky project. We didn't know where we were going and whether we would gain anything. We had so much luck. And then entered Boris Johnson - what more do you want?"