Tunnelling on the the Thames super sewer for London has reached the halfway construction point.

Photo:Tideway's King Edward Memorial Park foreshore site in Tower Hamlets (foreground) from the air

The giant machines digging the main super sewer tunnel - under construction to stop sewage pollution in the River Thames - have now tunnelled 12.5km of the 25km total length.

The tunnel now stretches as far west as Fulham and, eastwards, it has reached Blackfriars in the City of London – passing under 13 bridges including Albert Bridge, Westminster Bridge and Waterloo Bridge.

Andy Mitchell, Tideway CEO, said:

“I’m incredibly proud that this week, after more than three years of exceptional work by our teams across London, we’ve reached the halfway mark on the super sewer.

“There’s still a way to go but reaching this point on schedule is testament to the success of the team, who have achieved a huge number of engineering feats - including tunnelling under the river through a variety of ground conditions, building new pieces of land in the Thames to work in and digging giant shafts up to 50m deep below London.

“Once complete, not only will we have a cleaner river but there will be seven new areas of public space created along the Thames, transforming the embankment and creating new areas for Londoners and visitors to reconnect with the river.”

Shaft at Chambers Wharf, Bermondsey

As well as the main tunnel, a 1km connection tunnel is also currently under construction in Wandsworth.

So far, the tunnels have been constructed using four tunnel boring machines (TBMs). Two more tunnelling machines are due to start working in east London this year, creating the eastern section of the main tunnel from Bermondsey to Newham, as well as a slightly smaller 4km connection tunnel in Greenwich.

Construction of the tunnels has seen three million tonnes of material transported by river, avoiding 340,000 HGV journeys and more than five million kilometres of road transport.