THE reasoning behind the operation to shut Magdalen Bridge on May Morning - which cost almost £10,000 - has been called into question after the bridge was reopened early.

A cordon protecting the bridge at each end was removed at 7am - two hours before it could have been under a traffic order that permitted closure until 9am.

And almost as soon as barriers were lifted the 30 police officers and about 30 private security staff on duty were powerless to prevent scores of students running on to the bridge.

Three jumped off and none was seriously hurt, although three ambulances were on stand-by.

Last night, the authorities involved in the security exercise were labelled "heavy handed" for the way they managed the event, which was branded a "waste" of taxpayers' money.

Green city councillor Elise Benjamin, who had lobbied for this year's bridge ban to be lifted, said: "This was heavy-handed and frustrating.

"People will jump whatever. For the sake of three, four or five people jumping the rest of us are being excluded from the celebrations - it's a huge waste of money.

"What was the point of the closure in the first place? It's not made any difference.

"The best method is to take steps to educate people about the dangers.

"Both universities should be educating all their students about the injuries that have happened because a bridge closure isn't going to deter anyone."

The cost of the security operation was calculated at £10,000 after Oxford City Council contributed £5,700 towards the cost of stewards and security, Thames Valley Police said overtime for officers on duty cost £1,900, while Oxfordshire County Council paid £1,600 towards barriers and fencing.

South Central Ambulance Trust did not say how much the operation had cost them.

Last night, Oxford's top policeman, Supt Jim Trotman, defended the closure and said potentially treating large numbers of injured jumpers would have been a bigger drain on the public purse.

He said: "Unfortuantely we have seen in recent years many, many more people than just the few who foolishly jumped from the bridge and councillor Benjamin will be aware two years ago of the enormous number of injuries.

"We cannot ignore the fact that the emergency services and hospitals in Oxford are the agencies that feel the brunt of these self-inflicted injuries. I do not wish to inconvenience anyone in Oxford. The closure was well announced, there were alternate routes to cross the river and the bridge was not closed at the last minute."

Yesterday's estimated 8,000-strong crowd began to disperse after Magdalen College Choir sang their traditional Hymnus Eucharisticus from the top of the college tower.

South Central Ambulance operational manager John Willis added: "I think it is very sad people don't heed the warnings."

The authorities have indicated Magdalen Bridge would be closed for the foreseeable future, but Ms Benjamin has vowed to push for a complete reopening next year.