Training before the Boat Races between Oxford University and Cambridge University rowing clubs at Putney on April 2, 2017. Alberto Pezzali/Zuma Press/PA Images Organisers of the boat race say the event is still expected to go ahead despite the discovery of a World War Two bomb near the starting line.

Police were called to the Thames near Putney Bridge, just yards from the annual contest gets underway, on Saturday afternoon, after a passing sailor spotted the device.

Scotland Yard said the ordnance, believed to be an unexploded wartime bomb, was still submerged on Sunday morning and was being “assessed.”

Marine experts have examined the submerged bomb but the Oxford versus Cambridge clashes are expected to go ahead as planned.

Race director Michelle Dite said on Saturday: "Any decisions regarding changes to the event will be made in conjunction with the police.”

A Scotland Yard spokesman said: "Police were called by a member of the public at approximately 1.50pm on Saturday reporting what they thought to be World War Two ordnance on the Chelsea shoreline by Putney Bridge.

"Officers including the Marine Policing Unit attended. The item is currently submerged."

Thousands of people are expected to line the banks of the Thames to watch the 163rd edition of the Boat Race between the two universities.

Spectators have been urged to be extra vigilant following the recent Westminster terror attack.

The men's event starts at 5.35pm, while the women's race - in its 72nd year - begins at 4.35pm.