By Alison Freeman BBC News Online, London

Drivers say the new tariffs give cabbies and drivers a raw deal

Progress across one of London's most famous landmarks is slow because the traffic has deliberately been created by the cabbies as part of a demonstration.

As the number of cabs joining the go-slow across the major route over the Thames grows, the noise of horns sounding becomes deafening.

The drivers are angry about the abolition of higher fares for passengers travelling after 2000 BST which came into place in April. The higher tariff now applies later in the evening at 2200 BST.

Also drivers can no longer charge extra for additional passengers, with one fixed rate for all.

Cab driver Grant Davis, 39, gave me a lift across the bridge which is visible from City Hall.

'Effect on family life'

He said London Mayor Ken Livingstone's decision to change black cab's tariffs for the third time since he came into office was not only leaving drivers' out of pocket but also single travellers.

Mr Davis said: "I've been a cab driver for 15 years and I have to work more hours now than I did 10 years ago to make the same amount of money.

I thought it was really important that I came out to join the other cab drivers Jane Wolsey, cab driver

"If you need to work two hours extra a day to make the same money it can have a real effect on your family life. If you've got young kids and you get home at 8pm instead of 6pm, you're not going to see them.

"For a group of four or five people we can work out cheaper than getting the bus and we're not subsidised like public transport."

He estimated the cost of running his cab, including paying for the vehicle itself, at about �1,400 each month.

"People don't realise how much a cab costs to buy, it's �33,500, and we're self-employed."

"All we want is fair representation at Transport for London. We want to be consulted when changes are made. We need to feel we're valued and not being ignored."

Lower fares could mean more hours for drivers

Jane Wolsey, 36, who works part time as a black cab driver while her two children are at school gave me my second lift of the day.

She said: "I thought it was really important that I came out to join the other cab drivers today because we don't have a say on what's done to our fares.

"I became a cab driver because the hours are flexible but now I'd have to work longer hours to get the same money. I can't charge for more people or extra fares.

"I have to finish at 1500 BST so I can pick my kids up."