The lights will go out tomorrow on the Longbridge plant of MG Rover, Britain's last independent carmaker, in a temporary shutdown to clear a build-up of unsold cars.

The 6,500 staff at the West Midlands factory were informed last week of the company's plans to shut the factory from the finish of tomorrow's night shift until next Monday.

The decision to cut production came as MG Rover's parent company, Phoenix, suffered heavy criticism for using company funds to set up a £13m pension trust fund for senior management, leading to allegations that the directors were "asset stripping".

MG Rover - which rescued the plant from possible closure by BMW in 2000 - said the shutdown was needed to "balance stocks" held by dealers, preventing an overhang at a time of faltering sales.

Provisional figures from the European association of automobile manufacturers, ACEA, show MG Rover group sales within Europe have fallen slightly in the first 10 months of this year. Total new registrations by MG Rover to the end of October were 120,402, according to the ACEA, a fall of 0.5% compared with the same period last year.

A third of Rover's sales are in mainland Europe where they have been weak in France and the Benelux countries. Manufacturers such as Peugeot are also cutting overtime and production.

Figures from the Society of Motor Manufacturers and Traders show that MG Rover sold 85,567 cars in Britain in the first 10 months of the year, but reports in yesterday's Observer suggested a sharp fall in demand in recent weeks.

Last week MG Rover management met representatives of the Transport & General and Amicus unions at the Longbridge plant, with the unions outlining their concerns at the directors' £13m pension pot when the employee pension fund had a £73m deficit.

In 2002 the company lost £95m, and the roll-out of the new R60 model designed to replace the Rover 45 has been delayed for a further year following the collapse of an important supplier.

The unions were also concerned at the company's decision to take on a £10m loan provision, allowing the four co-founders of Phoenix to swap shares in MG Rover for £2.5m cash in 2005.

The company has said it will allow the unions to examine its financial statements and hold talks with Peter Beale, MG Rover's finance director, to allay fears of asset stripping.

MG Rover's directors defended the £13m pension payment, saying no contributions had been made to pensions in the previous two years - making the cash input worth about £1m a year for each director. The company plans to make a further contribution this year, but the size of the payment will be smaller, they said.

Critics of MG Rover have accused the company of poor corporate governance, but the company says it is willing to appoint independent non-executive directors.