Rail firm Connex suffered a blow in its bid to win the South Central rail franchise after criticism from London mayor Ken Livingstone.

Mr Livingstone's comments came as Connex was widely tipped to lose its franchise to run services between Sussex and London.

Speaking on the day he took up his role, the mayor said he would be "surprised"

if the company won his support to continue operating the services.

He warned that if the company attempted to run down its services following an unsuccessful franchise bid, he would seek emergency legislation to have it thrown off the line.

Mr Livingstone is a regular commuter between London and Brighton, where he has a home.

Connex is in a bidding war against Godiva, which owns Thameslink, for the franchise.

If it loses the lucrative South Central route, it would continue to operate between London and Hastings and on the South Coast line.

The company is promising a multi-million-pound investment in new rolling stock and infrastructure if it wins the franchise.

It has been criticised by passenger groups for using shorter trains than customers need, running more than a third of rush- hour trains late, cancelling services without providing information and dealing badly with complaints.

Connex spokesman David Ewart said the company's £1.45 billion bid to run the franchise meant improvements for passengers.

He said: "We are confident our bid will be accepted because it is robust and good value."

Connex has operated the services since 1996.