A syphilis-ridden 18th century mummy dug up from a Swiss church is the great-great-great-great-great- great-great grandmother of Boris Johnson, it has emerged.

The body was uncovered in 1975 during renovations on Basel’s Barfusser Church, but her identity has remained a mystery for more than 40 years.

Known as ‘Switzerland’s most famous mummy’, the woman was buried in front of the altar, and found wearing expensive clothes, with no signs of malnutrition, suggesting she had been wealthy.