Swiss scientists have solved the mystery of the unknown identity of a 230-year-old mummified woman in Basel.

Their research found that the woman is the great-great-great-great-great-great-great grandmother of the foreign secretary Boris Johnson.

The BBC reported that the mummy was discovered in 1975 during renovations at Barfüsser Church in Basel.

Scientists found that the corpse had been buried in front of the church altar. Her clothing and diet led them to assume that she had been someone of extreme wealth.

But with no gravestone, experts struggled to work out who she was.

The wood from her coffin dated back to the 16th century but that did not help identify her.

Scientists were, however, able to collect DNA samples from the woman's big toe for testing. The result were compared with other DNA samples to find that there was a 99.8% probability that the mummy was part of the Bischoff family.

After further checks, they could confirm that the mummy was Basel resident Anna Catharina Bischoff, who was born in 1719 and died in 1787.

It is thought she died after contracting syphilis, which was treated with a highly toxic dosage of mercury.

With her identity confirmed, they worked on compiling the rest of the family tree.

Anna Catharina had seven children, of whom only two survived.

One was a daughter, Anna, who went on to marry Christian Hubert Baron Pfeffel von Kriegelstein.

Following the rest of the Pfeffel family tree, five generations down the line showed that Marie Luise von Pfeffel married Stanley Fred Williams.

Their daughter went on to marry Osman Wilfred Johnson Kemal. They had a son together- Stanley Johnson, father of foreign secretary Boris Jonhson.