Unite, the BMW workers’ union, was last night under pressure to launch an investigation into officials’ handling of the mass redundancies at Cowley.

Former worker Stacey Rizzo, who was one of 850 temporary agency staff laid off in February, is also calling for the union’s regional leaders to hold a vote of no confidence to test the backing for Unite’s representatives at the plant.

Mrs Rizzo, 22, claims some workers were moved from temporary contracts to permanent ones just days after the redundancies were made and is unhappy at the selection process for it.

Neither the union nor BMW would confirm if any agency staff had been made permanent full-time employees. Bernard Moss, union convenor at the plant, was unavailable for comment.

In February, BMW laid off 850 temporary workers – all of whom worked for employment agencies – with a week’s notice, after a slump in car sales and production.

Mrs Rizzo said: “I feel cheated. Hundreds of people pay for a fair union but the reasons for doing that have been pushed out.

“If contracts were being made available, other agency staff should have been told.

“I don’t understand how they feel they can get away with it.”

In her letter of complaint to the union, Mrs Rizzo – who worked at the plant for four years before being made redundant in February – highlights the cases of other agency workers with excellent records who had even been given medicals for permanent positions but still ended up being axed.

She added: “There are several petitions circulating around the plant at the moment that show a vote of no confidence. One of those already has 200 signatures belonging to union members.”

The matter has now been taken up by Unite regional secretary Andy Frampton.

Mr Frampton said: “I have received a letter concerning circumstances which have arisen following BMW’s decision to release hundreds of agency workers at its Cowley plant, and I will respond to this letter as appropriate.

“The decision to dismiss these workers was opposed strongly by Unite, just as we will continue to oppose any legislation which encourages the creation of a two-tier labour force.

“In these extremely testing times for our members, they want to know that their union’s priority is to defend their rights and fight for their jobs.”

Mrs Rizzo said: “We want Unite head office to organise a mass meeting in order for us to put forward a motion of no confidence and have a democratic vote on who represents us.”

BMW spokesman Angela Stangroom said: “Since 2001, the company has given more than 1,400 BMW contracts to agency workers. We do not comment on any individual contracts awarded.

“The decision to award contracts rests entirely with the company and is based solely on an individual’s skills. However, we take any allegations of this nature very seriously.”

l Registration in the UK of new Minis built at Cowley were down 32.5 per cent, at 5,976, during March compared to the same month in 2008. Year to date the registrations are down 31.3 per cent at 8,474.

But a spokesman for BMW said that an “unexpected uplift” in sales for May meant each worker at the plant would be asked to work an extra three hours a week that month.