DAVID CAMERON, the most blue-blooded Tory heir apparent for four decades, is more aristocratic than even he realised. Research published today shows that he is, in fact, related to the Queen through an illegitimate royal child.

Not only that but researchers discovered that his wife is also descended from a royal mistress.

The young pretender to the Tory throne is William IV’s great, great, great, great, great grandson. He is related to the 19th-century monarch through Elizabeth FitzClarence, the King’s illegitimate daughter, one of at least ten children he had out of wedlock with Dorothy Jordan, his long-term mistress.

Samantha Cameron, 31, Mr Cameron’s wife, who is the creative director of an upmarket stationery company, also has royal connections. An analysis of her family tree by Cracroft’s Peerage reveals that Nell Gwyn, the mistress of Charles II, is Mrs Cameron’s great, great, great, great, great, great, great, great grandmother.

The family tree by Debrett’s Peerage, the genealogists, shows that the link between Mr Cameron, 39, and William IV makes him the fifth cousin twice-removed of the Queen. If Mr Cameron, who is expected to be declared the Conservative leader tomorrow, is ever asked by the Queen to form a government, he will, as tradition dictates, kiss the hands of the monarch, who is his own kin.

The royal connection has been traced through Mr Cameron’s grandfather, Donald Cameron, who married Enid Levita. Her maternal grandfather was Sir Alfred Cooper, the father of Duff Cooper, who was Sir Winston Churchill’s wartime Minister of Information.

Sir Alfred married Lady Agnes Duff, daughter of the 5th Earl of Fife by Lady Agnes Hay. Lady Agnes Hay was daughter of the 18th Earl of Erroll and Elizabeth FitzClarence, a bastard daughter of William IV by “Mrs Jordan”, who was an actress. She never married and had at least ten children with the King. Her real name was Dorothea Bland but when she went into acting she assumed the name Mrs Jordan as it was more respectable for married women to be on the stage.

Mrs Cameron’s father, Sir Reginald Sheffield, is the eighth baronet. The first was the illegitmate son of the 1st Duke of Buckingham and Normandy. The third baronet, Sir John Astley, 1828-94, married Eleanor Corbett, the granddaughter of the eighth Duke of St Albans. The first Duke of St Albans was the eldest of two illegitimate sons of Nell Gwyn, the actress, and Charles II.

Nell Gwyn came to London as an orange seller and became one of the foremost comic actresses on the London stage and one of the King’s favourite mistresses. The current Duke of St Albans — the 14th — sat in the House of Lords until the recent abolition of hereditary peerages.

The revelation of the family connection to William IV came as a surprise to Mr Cameron. A spokesman for him said: “I know for a fact that David is blissfully unaware of this. Journalists seem to know far more about his family history than he does. He hasn’t looked into his background, but he’s said as a passing joke that he’s going to. I can’t confirm or deny it.”

Charles Mosley, Debrett’s editor-in-chief, when asked about Mr Cameron’s illegitimate ancestor, said: “It was a scandal, but the 18th century was less prudish about these matters than we are. It wasn’t a secret.”

Mr Cameron’s aristocratic connections are in contrast to other recent leaders of the Conservative Party. Baroness Thatcher was a grocer’s daughter from Grantham, while the late Sir Edward Heath was the son of a railway worker. Sir John Major’s father was a circus trapeze artist and Michael Howard’s father was a Jewish refugee who fled Eastern Europe to escape the Nazis.

Patrick Cracroft-Brennan, from Cracroft’s Peerage, said: “Mr Cameron will be the most aristocratic leader of the Conservative Party since Alec Douglas-Home.”

William, Duke of Clarence, became William IV after the death of his brother, George, in 1830. His wife, Adelaide of Saxe-Meiningen, bore him no legitimate heirs.

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