Fines imposed on drivers at a bus lane in Wimbledon have soared by more than 4,000 per cent in just three years.

Since 2010 the bus lane at the junction of Queens Road and Wimbledon Bridge has generated a total of £368,761 - £337,378 in 2012/13 alone - in fines according to figures obtained from Merton Council at the request of Conservative councillors.

Fines jumped from £7,451 in 2010/11 to £23,932 in 2011/12 to  £337,378 in 2012/13 following an extension to the bus lane of 20 metres - a total increase of 4,428 per cent.

Councillor Janice Howard, Merton Conservatives’ transport spokesman said: "These figures are staggering.

"We all know that the bus lane on Hartfield Road is just a cash cow for the Labour council, but to find out that they have a herd of them is astonishing.

"It is this sort of pernicious and over-zealous enforcement which makes residents and visitors to Merton think twice before coming again.

"Enforcement should be measured and fair.

"This jump in fines shows that Labour is just hitting an easy target."

The bus lane in Hartfield Road has caused equal controversy since it introduced in in November 2011 which in its first nine months alone generated £500,000 in income.

It too has been criticised for being a "cash cow" capable of trapping drivers as the road merges into one lane without adequate signs to warn drivers they are entering a bus lane.

However Councillor Judy Saunders, cabinet member for environmental cleanliness and parking, has said fines at the Hartfield bus lane are actually reducing indicating that enforcement is working.

She said: "Traffic congestion is one of Merton residents’ top concerns and enforcing traffic regulations fairly is one way the council tackles this.

"In areas of the borough where there are higher levels of PCNs issued this is due to low levels of compliance.

"Motorists change their behaviour as a result of enforcement. For example there has been a big fall in fines for entering the Hartfield Crescent and Hartfield Road bus lanes.

"This shows that enforcement works and stops traffic congestion.

"As part of the council’s "firm but fair" approach, we have published our enforcement manual online to help road users gain a clearer understanding of how our traffic enforcement policy works.

"We have also launched a parking charter so that both the council and motorists know what is expected of them.

"Fines for traffic contraventions contribute to the costs of the Freedom Pass which costs the council £8.6m per year."