Hundreds of people, mainly students, traditionally jostle on to the historic Magdalen Bridge (it's pronounced 'maudlin') during the celebrations of one of the best-known traditional English customs.
Some make the daring leap from the parapets into the River Cherwell, often wearing formal evening clothes after staying up all night.
In recent years the bridge has been closed to protect both revellers and the structure itself. The closure has not been popular.
It had been hoped that the bridge would be strengthened in time for this year's May morning, which falls on a bank holiday - meaning bigger crowds than usual.
Morris teams including Kirtlington and the Oxford sides have long played a part in the festivities. William Kimber - the 'father of the morris' - often performed in them.
A joint statement on the bridge closure has been issued by Oxford City Council, Oxfordshire County Council and Thames Valley Police. It says:
"Plans are underway to re-open Oxford's Magdalen Bridge to the public for May morning 2001, after work has been completed to strengthen the parapets. But the work will not be done in time for this year's celebrations, meaning the bridge will again have to be closed for two hours on May 1 to protect the crowds who gather to hear the singing.
"A team made up of the City Council, County Council, Thames Valley Police has, with the support of Oxford University, Oxford Brookes University and the emergency services, been looking at ways of overcoming the dangers posed by large numbers of people pressing onto the bridge for the 6am performance by Magdalen College Choir.
"The main hazard relates to the parapets of Magdalen Bridge, which are unable to stand the likely pressures caused by large crowds expected on May morning, which this year falls on a bank holiday.
"The team has now been able to find a way of solving the technical problems and the County Council is planning to strengthen the bridge parapets in time for May 2001. However it will not be possible to undertake all the necessary planning work, secure the necessary consents and carry out the work in time for this year's celebration.
"Therefore because of concerns about public safety it will be necessary for the County Council as Highways Authority to close the bridge for about two hours on May morning during this year's traditional festivities. The County Council has provided the money to strengthen the bridge parapets in time for the following year.
"Oxford City Council and Oxford University will be providing stewards for this year's event. A small number of police officers will also be present to ensure a safe event.
"County Council Chief Executive John Harwood said: 'We want May morning to return to being the picturesque spectacle it was before the crowds became so great that the bridge was not able to safely contain them. The work we will carry out should ensure that this is the last time we have to close the bridge.'"
©2000 Simon Pipe, Mark Rogers, The Outside Capering Crew