1. ITV Report

Mummified woman was seven-time great grandmother of Boris Johnson

The mummy has been identified as the seven time grandmother of Boris Johnson. Credit: SRF/PA

A woman, whose mummified remains were found in a Swiss church decades ago, has been identified as an ancestor of Foreign Secretary Boris Johnson.

The preserved remains were found 43 years ago at the Barfuesser Kirche in Basel and after intense studies by genealogists and molecular geneticists, she has been identified.

The body belonged to Anna Catharina Bischoff who was born in 1719 in Strasbourg and died in Basel.

Bischoff had married a church minister and had seven children but only two girls survived.

One, also called Anna, married Christian Hubert Baron Pfeffel von Kriegelstein, and six generations later along came Stanley Johnson, father to Boris.

DNA material was extracted from the mummy's big toe. Credit: SRF

Scientists confirmed her identity by extracting DNA material from the big toe to compare the genetic profile with surviving members of the Bischoff family.

The results showed a 99.8% probability that the descendants were from the same maternal family tree.

Anna Catharina Bischoff died of mercury poisoning after undergoing treatment attempting to cure her of syphilis. Credit: SRF

Anna Catharina Bischoff's body was uncovered in 1975 while renovations were being done on the Barfuesser church.

She was buried in front of the altar and was described as well fed and wearing good quality clothes suggesting she was a wealthy lady.

Anna's daughter married Christian Hubert Baron Pfeffel von Kriegelstein, an ancestor of the Johnsons. Credit: SRF

She died in 1787 at the age of 68, from mercury poisoning, scientists believe.

She underwent intense mercury treatment in a bid to cure syphilis, which she is thought to have contracted while caring for patients with the sexually transmitted disease.

However, the mercury also preserved her remains allowing researchers to find out more about her life and her descendants.