Ken Livingstone is secretly planning much wider use of congestion charging across London if he is reelected as mayor on May 1, The Times has learnt.

He did not mention the plans in his transport manifesto, announced yesterday, because he fears that he may lose votes in outer London boroughs.

A source close to Mr Livingstone said that Transport for London was developing plans to introduce charging to other congested parts of the capital but was under strict orders not to disclose anything before polling day.

Before the last mayoral election Mr Livingstone failed to make clear that he was planning a significant rise in the £5 congestion charge. His plan to increase it to £8 emerged after he was re-elected. This time, his manifesto contains no new commitments on congestion charging but reaffirms his decision to charge the most fuel-inefficient cars £25 a day from October.

In a statement apparently timed to coincide with Mr Livingstone’s manifesto, TfL announced it had rejected a claim by Porsche that Mr Livingstone would exceed his powers by introducing the £25 charge.

Porsche has said it will seek a judicial review of the increase and has argued that it is disproportionate because it would make a “negligible” impact on carbon dioxide emissions.

Mr Livingstone said: “Porsche have a vested interest in attempting to block this scheme, against the interests of Londoners. They should focus their attentions on cutting CO2 emissions from the cars they produce, rather than pursuing this pointless legal action.”

His manifesto promised a “hassle-free system for paying the congestion charge”. Drivers will no longer have to remember to pay because they will be able to have payments deducted on entering the zone. The tag-and-beacon technology that will enable this payments system would also allow Mr Livingstone to introduce charges on congested roads outside the existing zone.

Gantries over the road detect prepaid tags in passing vehicles and deduct the appropriate fee. It could allow charges to be set for using a stretch of road rather than the present system of covering a whole area.

In 2006, TfL identified areas that might benefit from congestion charging. They were Harrow, Hounslow, Kingston, Sutton, Croydon, Bromley, Ilford, Romford and Wood Green.

Since 2006, TfL has been publicly silent on the question of extending congestion charging beyond the original zone and the western extension.

Mr Livingstone’s manifesto includes commitments to introduce a fleet of hybrid-powered buses, payment by mobile phone for Oyster cards, minute-by-minute bus information technology, fare concessions for older Londoners and students, and “a revolution” in cycle facilities.

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