Connex was fined for poor service in January 2002

Connex, which runs services into London Bridge, says rush hour trains will not be affected.

But off-peak passengers may find some trains are no longer running from the end of this month.

Forty of the company's 1,700 services will be cut but the company has denied suggestions it will cause chaos.

It says the changes will provide recovery time in the schedules and will lead to a 5% improvement in performance.

A spokesman said: "We realise no-one likes to see fewer trains, but the new timetable allows more 'breathing space' for us to improve the performance and punctuality of the service."

More changes are likely once the first phase of the Channel Tunnel Rail Link opens in the autumn and Eurostar trains move onto the new line during off-peak hours.

Connex will continue running its South East services until December

Connex said this will improve journey times to Folkestone and Ashford.

Routes to London's Victoria and Blackfriars stations will also need to be adjusted to accommodate Eurostar on the new route.

In June Connex lost its franchise to operate services to Kent and Sussex, which had been due to run until 2006.

One in five Connex South Eastern trains were running late at that time.

But the Strategic Rail Authority (SRA) said poor financial management, rather than its "operational competence" was to blame.

An interim company is due to take over Connex's South Eastern trains in December until a new private operator is found.

Connex is the latest in a line of train companies to cut services to try to make trains run on time.

On Monday South West Trains said it was cutting more than 70 services a day.

The SRA said the new winter timetable, which starts operating from 28 September, includes cuts in off-peak trains to improve reliability for peak-time services.