Grounded...college choir that has sung from the rooftops for 106 years

But this year, health and safety regulations have been blamed for keeping the choir firmly on the ground.

Instead of climbing the 163ft tower, the choristers had to lead the assembled crowds in their rendition of Hail The Day That Sees Him Rise from the lawn outside the Chapel on May 1.

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On song: How the St John's choir usually performs from on high

The much-celebrated choir has been ascending the tower to celebrate Christ's ascension to Heaven by singing the Ascension Day Hymn at exactly midday since 1902.

Now it has started a heavenly row among college dons.

For the Dean of St John's, Dr Peter Linehan, the break with tradition was such a blow that he was moved to write an angry letter to a newspaper decrying "the custodians of our health and safety".

Other academics, however, have said it was simply caused by a hailstorm and that the tradition will be resumed next year.

Speaking to The Mail on Sunday, Dr Linehan fumed: "There are draconian rules now about having people up towers. This year was the first time since this very old custom was established that the choir has been on the lawns.

"It makes me sad. Health and safety concerns are increasingly intrusive.

"The view is taken now that the Government – or whoever legislates about these things – doesn't like the idea of choirboys being blown off the top of chapel towers, even though that's never happened before."

But other senior staff at the college, one of Cambridge University's wealthiest, were keen to play down the Dean's comments.

Rev Duncan Dormer, the Dean of the Chapel, said the decision for the choir to remain on the ground was taken purely because of the weather.

He said: "We had a brief hailstorm shortly before we were due to go up the tower, making the roof potentially dangerous. So unfortunately we weren't able to go up the tower. It has happened occasionally in the past."

Rev Grant Bayliss, the Chaplain, said: "The weather let us down. By the time it came to climb the tower, the top as like a swimming pool and it just wouldn't have been practical to go up there, so we all knew it wasn't going to happen.

"The ultimate decision was made by the building superintendent but we knew the outcome before he arrived. There are two narrow spiral staircases inside the tower, so it would have been lunacy to try to climb it.

"There have been other occasions where the weather has prevented us climbing the tower.

"It was a shame but we have every intention of going back up there next year and we hope the weather permits it."

When informed of these comments, Dr Linehan said: "If you've spoken to them and that's what they've said, then there's nothing more to add."

The St John's custom dates from 1902 and was begun because of a dispute between by the then Director of Music, Cyril Rootham, and physicist Sir Joseph Larmor.

Sir Joseph insisted that it was pointless singing from the tower as not a word of it would be heard down below, and that was a scientific fact.

Rootham was keen to prove him wrong and saw Ascension Day as the perfect time to do it.

Without telling anyone else in the college, Rootham ordered the choir to climb the tower and, as the clock finished striking noon, they started to sing an Ascension Day hymn.

To Rootham's delight, he saw a puzzled Sir Joseph fling open his window in the court below to see where the music was coming from. The event proved popular and has since become a yearly tradition.

To rub salt into Cambridge's wound over this year's debacle, Oxford, which has a very similar, and much older, tradition each May 1, on the same day saw a choir climb Magdalen College tower and sing their hymn undaunted. And in Latin.