The amount of sewage spewing into the Thames from the Putney combined sewer overflow (CSO) was described as "embarrassing" by one of the world's top rowers yesterday.

Roz Savage, the first woman to row across the Atlantic, Pacific and Indian oceans, rowed to the CSO under Putney Bridge yesterday to demonstrate the extent of the sewage.

She was joined by members of the Thames Anglers Conservancy Society and river charity Thames 21, who met to press for work on the Thames Tunnel super sewer to begin now.

The Putney Bridge CSO discharges about 34 times a year and spews 68,200 tonnes of sewage, from the annual total of 39m tonnes, into the river.

As little as 2mm of rain can cause the sewer to overload and spill into the Thames, killing fish and other wildlife.

Experts say the sewage can also lead to serious health problems, such as stomach bugs, cholera and typhoid.

Ms Savage, ambassador for Thames Tunnel Now (TTN) campaign group, said she saw condoms, sanitary towels and faeces spewing into the river just yards away from restaurants and boating clubs.

She said: "I actually find it quite embarrassing that a real 21st century city like London should have a 19th century sewage system.

"I think it is so important to not have this much sewage going into the Thames. I know the Thames Tunnel is going to be completely inconvenient and noisy for some people, but which would they prefer - a few years of construction or a stinky River Thames?"

Debbie Leach, chief executive of Thames 21 said: "Fish suffocate, the eel population can't get up the river. It used to happen once in a blue moon, but now London has become bigger and the heavier downfall means it is happening more regularly.

"It is going back to the days when people would have to have their stomachs pumped if they fell in the Thames."

Chas Newen, of Newens Marine Company Limited based next to the CSO said: "The Thames Tunnel can't come soon enough for us, the disruption is worth it. It is horrible, it is stinky."

A public meeting to discuss issues about the Thames is taking place on February 7 at the London Rowing Club, Embankment, Putney at 6.30pm.

Submit your comments to the Thames Tunnel public consultation at thamestunnelconsultation.co.uk before the deadline of Februrary 10.