Gove used Cameron’s Downing Street cabal of Old Etonians – which includes Ed Llewellyn, his chief of staff; Oliver Letwin, his minister for government policy; Jo Johnson, his head of the policy unit; and Chancellor George Osborne’s chief economic adviser, Rupert Harrison – to draw unfavourable comparisons with the close-knit cabinet assembled by the late-Victorian Tory prime minister, Robert Gascoyne-Cecil, the Marquess of Salisbury.

“At the beginning of the 20th century, the Conservative cabinet was called Hotel Cecil,” Gove said. “The phrase ‘Bob’s your uncle’ came about and all the rest of it. It is preposterous.”

A stalwart of the ruling class, the Eton-educated Lord Salisbury was ridiculed for nepotism and cronyism, at a time when membership of the ruling class was a nobleman’s privilege and the public-school dominance of the corridors of power mostly went unquestioned.

The clearest beneficiary of Lord Salisbury’s largesse was his favourite nephew, Arthur Balfour, for whom he pulled strings first in 1873, to get him elected unopposed in a safe seat, and then in 1902, to anoint him as his successor. When Lord Salisbury surrendered the seals of office – without first notifying his government – it was Balfour whom the King asked to form a government. Hence where the phrase “Bob’s your uncle” is said to have come from.

In the first episode of his The Making of Modern Britain series, Andrew Marr also suggested that the phrase was coined around the turn of the century. That ‘nepotism’ is also thought to be derived from ‘nephew’ makes the link all the more clear.

However, not all etymologists are convinced: the origin of the phrase is notably absent from the Oxford English Dictionary.