He was given up for adoption at birth. He never knew his biological parents. And for 36 years he knew nothing of his personal and political roots, or what drove him from youth to pursue the Liberal tradition.

Now Matthew Taylor, the Liberal Democrat MP, has revealed the extraordinary story of how he discovered his real mother – and that he is descended from a prominent Liberal who served in the House of Commons for almost 30 years.

Finding his mother was shock enough; discovering that politics really is in his blood was almost more overwhelming.

“The odds on my having followed in my great-grandfather’s footsteps as a Liberal MP were minuscule,” he said. “In that moment I felt everything I thought I knew about why I am who I am was turned upside-down. In the battle between nature and nurture, nature seemed to be having a laugh.”

In 1963 Taylor was taken from his mother at only a few hours old and was given up for adoption. He was brought up by Ken Taylor, a television scriptwriter, and his wife Jill, a stage manager, who had discovered that they were unable to have any more children.

Taylor enjoyed an idyllic childhood divided between Cornwall and London, where he spent many an hour in television studios watching his father’s work, which included The Camomile Lawn and The Jewel in the Crown, being filmed.

He might have been expected, like his sister Vikki, to have followed a career in theatre or television: Vikki grew up to become executive director of the Royal Shakespeare Company. Instead, Taylor was always strongly drawn to politics – and Liberal politics in particular.

Even at school he was rooting for the Liberals, although it was unfashionable in the wake of the Jeremy Thorpe scandal. At university he was elected on an alliance ticket as president of the Oxford Student Union, when being a Labour activist was far more trendy.

After leaving Oxford he became the party’s economics researcher. By 24 he was in the Commons as a Liberal MP for Truro. Only at the age of 36 did he decide to investigate his biological roots – and began to uncover a series of remarkable coincidences.

When he visited the office holding his adoption records, he discovered that, quite separately, his real mother had at the same time decided to try to find him. Maggie Harris, who had become pregnant with Taylor during a brief affair while an art student in London, had written to the office only weeks earlier asking for information about him.

He wrote back, telling her only that he was happy and had a good job – but not mentioning that he was an MP.

Then came the return letter. Quite unprompted, Harris told her son, in her first few sentences, that he was descended from a Liberal MP. She also mentioned that she was a local councillor and was in the middle of an election campaign.

It was not only Taylor who was amazed by the revelation. His adoptive parents, who had backed his attempts to find his birth parents, were equally surprised. “We were completely gobsmacked,” said Jill Taylor. “We never knew politics was genetic.”

Taylor’s ancestor was Sir Percy Harris, whose children emigrated to New Zealand. Harris, who was educated at Harrow and Cambridge, was elected in 1916 as MP for Market Harborough at a by-election.

He lost the seat but was reelected as MP for South West Bethnal Green, hanging on to his seat until 1945, after almost every other Liberal MP within 100 miles had lost theirs.

Taylor has proved equally tenacious. In the 1980s and 1990s he retained his Truro seat while his Liberal colleagues were reduced to a small guerrilla force in parliament.

Harris, who became deputy leader of the Liberals, was described as an MP who spoke “frequently on every kind of topic in the Commons”. Taylor, in turn, has held almost every senior spokesmanship that the party has to offer to such an extent that it became something of a joke in parliament. While Harris was elected deputy leader, Taylor recently missed out on the same post by two votes to Vince Cable.

He also found that he had several physical traits in common with his ancestor MP, including terrible eyesight.

Upon meeting his mother in New Zealand, Taylor discovered that the coincidences with his genetic family did not stop there. His great-aunt, Lucille Harris, had played a leading role in a BBC radio play, In Other Days; it had been written by his adoptive father Ken in the 1950s.

Taylor’s adoptive father had also written a television series about the suffragettes, Shoulder to Shoulder – and Harris, it turned out, had been a staunch supporter of women’s suffrage.

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