麻豆社

The Mayor of London wants London's rivers to be clean enough that they can be swimmable in 10 years time. But is that realistic?

The River Roding - London's third largest river - has been earmarked as a potential swimming spot, but it's often polluted by rubbish, sewage and run off from the road.

Campaigners say all that needs to be addressed, but the idea could be achievable with investment.

麻豆社 London's Environment Correspondent Tom Edwards has more.