Almost £12 million is to be spent on Brighton's Royal Sussex County Hospital's dilapidated operating theatres to bring them up to standard and cut waiting lists.

The work includes building a seventh main theatre so more patients can be treated.

Three of the hospital's six main theatres have already been revamped but work needs to be done on the rest for them to meet new health and safety standards.

If the work is not done, the Royal College of Surgeons could class them as unfit for use.

The theatres, which are more than 30 years old, have poor ventilation while electrical and other engineering facilities are outdated. The floors are also in poor condition.

Two of the now revamped theatres were shut at Christmas because of a leak from a pipe that caused water to seep up through the floors.

New floors are to be laid as part of the £11.8 million development and will include a damp-proof membrane to protect against flooding.

The theatres will also get new equipment and changing rooms and staff areas will be rebuilt to include better storage and office space. All the theatres will have proper ventilation facilities.

The work is due to start in September and will be phased to try to avoid disruption to patients and operating lists.

Surrey and Sussex Strategic Health Authority is supplying the money for the scheme.

Jayne Black, general manager for critical care and anaesthesia at the hospital, said: "We are delighted with the support from the health authority.

"This £11.8 million will deliver up-to-date theatre facilities and the additional theatre will help us work towards the further reduction of waiting lists."

All upgrading work and the new theatre are expected to be finished by 2006.