The Army will be storming Rochester Bridge tonight to carry out a mock demolition of the crossing as part of a training exercise.

Sappers from the Royal School of Engineering, based at Brompton Barracks, will be conducting the operation using no live explosives and ammunition.

In 1940, during the Second World War, when invasion threatened, it could have happened for real, with soldiers destroying the historic bridge to try to stop Hitler’s troops advancing on London.

Blowing up and building bridges is a key role for the sappers in combat and the operation, codenamed Exercise Bridge Dem, will give 22 personnel a rare chance to test out their skills on a working civilian bridge rather than a military training ground.

Normally such exercises take place out of public view so this will give people of Medway a unique opportunity to watch the Army in action.

Troop commanders will attach dummy charges from the road footway and place them on the arches as if “blowing” the bridge for real.

The soldiers will arrive by boat at about 9.15pm and will remain on the river at all times. The demolition is due to start at 10pm.

There will be a total of 22 taking part, comprising 18 regular British Army troop commanders, one reserve officer and three students.

In addition there will be eight supporting troops and staff. It will take place on the old bridge only.

The bridge will be partially closed.

An Army spokesman said: “There won’t be any bangs as this is not a military training area and no munitions or pyrotechnics will be used.

“This presents a unique opportunity to provide realistic training in a complex urban environment.

“We has a long history of working with the Rochester Bridge Trust."

Sue Threader, the bridge clerk and chief executive of the trust, said: “We have a long-standing relationship with the Royal Engineers that dates back some 160 years to the demolition of the medieval bridge at Rochester.

“The two organisations continue to work closely together, particularly in the field of education. I am pleased we are able to assist with this training exercise for young officers.”

Among the guests invited are Rochester and Strood MP Kelly Tolhurst, Medway mayor Cllr David Wildey and the High Sheriff of Kent, George Jessel.

Spectators are advised to arrive at 9pm and the exercise will conclude at 11pm.