The mayor of London has called out the ‘scandalous’ increase in instances of sewage flowing into the capital’s rivers, urging Thames Water to ‘get a grip of the situation’.

Between April and December 2023, sewage was released into London's waterways for 6,590 hours, according to City Hall’s analysis of Thames Water data.

The figure is more than four times higher than the 1,420 hours recorded during the same period in 2022.

These discharges include treated sewage as well as overflows of untreated sewage and storm water during high rainfall, which is permitted by the Environment Agency.

London mayor Sadiq Khan has written to Thames Water’s new CEO, Chris Weston, asking for reassurance that the company ‘will fulfil its obligations on environment including cleaning up our rivers and tackling pollution discharges’.

The mayor said: ‘Frankly the current state of some of our rivers is appalling and only getting worse. Thames Water urgently need to up their up their game, and get a grip of the situation.

‘At the same time, ministers are standing by and letting more and more dirty sewage flow into our rivers. We need tougher legislation that forces water companies to act as a matter of urgency.’

A Thames Water spokesperson said: ‘We regard all discharges as unacceptable and are committed to reducing the need for them.

‘The Thames Tideway Tunnel, a £4.5bn investment, is nearing completion.

‘This project, combined with previous upgrades we’ve made to our London sewage works and the building of the Lee Tunnel, will capture 95% of the volume of untreated sewage currently entering the tidal Thames in a typical year.’