Women teachers in London who depend on cars to get to school could feel their safety is threatened by congestion charges, warns a teachers' union.

The charges to be introduced next month are intended to reduce overcrowding on the capital's roads.

But a teachers' union says that inner-city teachers, particularly women, who feel safer driving to school, will now find it too expensive.

There are also fears that the �5 a day charge - which would cost teachers �100 per month - will aggravate the staff shortage which is already most acute in inner-city schools.

High housing costs mean that many staff in central London schools commute into work.

Unsafe streets

And the extra travel charge could make it even more difficult to recruit and retain staff for inner-London schools.

The National Association of Schoolmasters Union of Women Teachers says that teachers in high-crime areas might commute by car because of fears about safety.

The union also says that many teachers might have to carry large numbers of books for marking, which can make public transport impractical.

Kathy Duggan of the NASUWT, who represents teachers in inner London, says that the charges could be enough to price teachers out of their jobs.

Pay cut

And she says cars are a necessity rather than a luxury for many teachers.

"Primary schools are often in back-streets and not near public transport. And teachers might be carrying 30 books and a poster display. They might also have their own children to collect."

Even though inner-city teachers might need to drive, she says the charges will make it untenable - and as such staff might be forced to consider changing jobs.

There are no discounts planned for public sector workers who travel into the central London areas which will incur congestion charges.

But Kathy Duggan says that there should be a re-think for key workers.

Young teachers in London can earn less than �400 per week before tax and deductions - and for those paying �25 per week in congestion charges, it would represent above a 6% pay cut.

In terms of take-home pay, the impact would be even higher.

A spokesperson for the London Mayor's office, said that there was great awareness of the need to ensure safety on public transport - and that the bus network had been made safer.

The introduction of charges could be the time for people who commute by car to test the public transport alternatives, she said.

And in terms of cost, travelling to work by car, and getting stuck in heavy traffic, has its own financial costs, she said.