A storm over tea cups is threatening to disrupt production at Pinewood Studios, the home of Carry On films and Harry Potter.

The media and entertainment union served notice to management today of a planned strike ballot after months of talks failed to stop a simmering row boiling over.

Tom Bell, a spokesman for BECTU, says there is a point of principle at stake over bosses' unwillingness to recognise the union on terms and conditions of pay.

But Andrew Smith, corporate affairs director at Pinewood, argues that the whole dispute arises out of a simple desire to cut back a tea break that has stretched from a regulation 15 minutes to 30.

"It really is a storm in a teacup," he said. "I have a very good relation with colleagues and just don't understand why this has all blown up when all we are doing is trying to talk about one afternoon break."

Behind the scenes at the studio, where they are working on a film of Gulliver's Travels starring Jack Black, there have been wider ructions over 10 expected redundancies and fears of wider cuts to come.

Approximately 70 staff across the group's sites at Pinewood, Shepperton and Teddington will be eligible to take part in the BECTU ballot, which gets under way next Friday. If the union secures a mandate for industrial action, strikes are likely.

"In all my years as a full-time union official, I have never met with the levels of duplicity being displayed by the Pinewood Group's managers," Bell said. "We now have no alternative but to ballot in order to defend the rights and interests of our members."