The baby son of the Duke and Duchess of Cambridge could be named after the mythical King Arthur – if punters are to believed.

Bookmakers have seen a flurry of bets placed on William and Kate’s infant boy being given the moniker of the famous leader of the Knights of the Round Table.

William Hill’s Rupert Adams said they had a very busy day with bets totally almost £100,000 placed by punters, with the 2-1 favourite Arthur and second place James 4-1, best backed.

Harry Aitkenhead from Coral said: “At the moment Arthur is now 7-4 with Coral. James 4-1 with Philip and Albert at 6-1 the only other two with single figure odds.

“Anything else would be a big surprise.”

The moniker has a strong royal pedigree as it is one of the middle names of both Charles and William.

Arthur supposedly lived in the 5th or 6th century and is said to have unified the country and set up his court at Camelot before being killed in a final epic battle.

Once popular, the name fell out of fashion but has had a revival in recent years. Former prime minister David Cameron has a son called Arthur.

The William Hill spokesman said the favourite name with punters, for William and Kate’s previous children, proved correct and history could repeat itself with baby number three.

“The odds correctly predicted the first two baby names and, should Arthur be announced, then we will have had a hat-trick,” said Mr Adams.

He added: “Let’s hope he is more King Arthur than Arthur Daley.”