When the first glow of daylight heralded the arrival of the fabled 'merrie month' beloved of poets and dreamers, the crowds of 'May Morners' packing into Oxford's historic centre must have breathed a collective sigh of relief.

The earlier showers had seemed to stop in time for the gathering of students and older celebrats to enjoy the traditional celebrations -- and they were determined to do so, come what may.

But as a hush descended when the Magdalen College Choir began their traditional recital to the thousands of people packing the High Street and Magdalen Bridge, the rain arrived almost as if on cue, resulting in a sudden sea of brollies lifted aloft by the faithful traditionalists.

The 13 boys and 12 male choristers enchanted the listening crowd with a rendition of the 16th century madrigal "Now is the month of Maying," followed by an anonymous piece "O Lusty May" dating back to the 14th century, and ending to huge applause with the College Hymn, "Hymnus Eucharistus" written by the College's organist, Benjamin Rogers in the 17th century.

The squall soon passed, and the unseasonal temperatures and a brisk south-westerly breeze did not prevent a few diehards from scaling the seven-foot metal barriers guarding the parapets of the bridge and leaping feet-first into the turgid shallows of the River Cherwell, despite signs warning against serious injury.

Many of the revellers had come from college balls held the previous night to celebrate the tradition.

Paul Thompson, 23, Tom Barclay, 22, and Alex Baer, 21, all students at the Oxford Brookes University, had dispensed with their black ties after joining fellow members of the University's Officers' Training Corps for their annual dinner at Falklands House.

Mr Thompson said: "We've had a very good night and sleep denial is what we do best."

Myrtle Vincent, a volunteer for the Save the Children Charity, was joined by colleagues selling posies to passers-by as their joined the throng.

"I've been doing this for about 15 years now and we usually make about £220 for the charity from these lovely flowers which come from about 20 different gardens."

Thames Valley Police adopted a 'low-key' coverage of the event, handing over responsibility for the event to Oxford City Council, whose private security officers limited numbers of people crowding on to Magdalen Bridge to 8,500.

Inspector Stuart Craik, in charge of Oxford police, said: "All reasonable steps have been taken to ensure than all goes well, but it's all in the hand of the city council whose stewards are in charge."