Britain's biggest bus operator, FirstGroup, yesterday demanded the introduction of congestion charging schemes in "most cities" after enjoying a bonanza in bus use since London's £5-a-day fee for car drivers began in February.

A 23% jump in turnover from buses in the capital helped the company raise its underlying pre-tax profits by 1.8% to £56.8m.

FirstGroup has won eight new contracts to operate routes in London as part of mayor Ken Livingstone's initiative to enhance services. The company now operates 1,300 London buses and has seen average speeds rise 15% since congestion charging.

Chief executive Moir Lockhead said: "We would like to see congestion charging in most cities. It is a great help to traffic flows - not just to buses but also to emergency vehicles."

At present, only Edinburgh and Bristol have advanced plans to charge car drivers. Other cities have put proposals on the back-burner, following public opposition.

FirstGroup's overall profits from buses edged up 0.6% to £46.2m. Earnings from rail operations slumped by a quarter to £22.1m as government subsidies fell by a net £17m.

The group this week won the Thames Trains commuter franchise from rival Go-Ahead Group; it will be merged with its First Great Western inter-city network.

Mr Lockhead said he was requesting more money from the Strategic Rail Authority for longer trains, more frequent services and the introduction of 125mph inter-city rolling stock on shorter routes from London to the Thames Valley now served by 90mph locomotives.

He said there was scope to increase capacity on routes out of London's Paddington station by up to a fifth for a "relatively small amount of money".

Speaking 10 years to the day from royal assent to the bill which privatised Britain's railways, Mr Lockhead said the company had made a net loss from running trains. "We've invested more than we've earned," he said.

He said privatisation had delivered growth in passenger numbers and £500m worth of new trains on FirstGroup's rail routes and insisted that problems had largely been caused by infrastructure flaws. "Years and years of neglect have resulted in the tracks becoming more fragile as we've grown services."

FirstGroup's shares fell 9.75p to 293.5p.