TAXI journeys could go up by 50p per trip because of rising fuel costs.

Transport for London (TfL), which governs London's taxis, has agreed to let cabbies add the charge to their meter if diesel prices reach 154p per litre by next February.

This decision has been made because the cost of fuel has gone up by 27 per cent since Tfl set the 2008 taxi rates.

If the charge comes in black cab drivers will display a sticker which states that the supplement has been introduced by TfL because of the high cost of fuel.

Chief operating officer of TfL's surface transport Jeroen Weimar said: "Black cabs are an invaluable part of London's transport network, and over 250,000 people use them every day.

"We recognise the burden that fuel price increases have had on taxi drivers this year.

"Fuel makes up about 10 per cent of the costs of running a taxi and unlike many other trades, taxi drivers cannot put prices up to reflect increased costs.

"Passengers can rest assured, however, that any increase in fares as a result of this decision will be taken into account when TfL sets taxi tariffs in April 2009."