Silvertown Tunnel construction work
“Jill” is lowered into place by the Riverlinx team in Silvertown

Contractors have begun to lower into place the machine that will build the Silvertown Tunnel, marking a new milestone for mayor Sadiq Khan’s controversial road project.

Riverlinx, the company that is building and will operate the new tunnel for Transport for London, which the mayor chairs, has lowered the first parts of the tunnelling machine into its launch chamber at Silvertown, on the north bank of the Thames.

When complete, the tunnel boring machine (TBM) will make its way underneath the river towards the Greenwich, before turning around and making its way back towards east London. The “eye”, which will guide the machine under the Thames, was lowered into place last month.

Tunnelling work is set to begin in August, this website understands, four months later than originally planned. The £2 billion tunnel, which will include dedicated lanes for HGVs and buses, will link the Greenwich Peninsula and the Royal Docks. Khan insists that the road is needed to deal with notorious queues at the northbound Blackwall Tunnel, opponents say it will fail to do that and will worsen congestion on both sides of the Thames.

Both Blackwall and Silvertown tunnels will be tolled when the new road opens in 2025 – a measure Khan says is needed to control traffic. The tolls will also pay off the construction costs.

News of the milestone for the project comes little more than a week after Newham’s elected mayor, Rokhsana Fiaz, told a conference organised by the Stop the Silvertown Tunnel Coalition that she was “confident we can make interventions to slow down construction of the Silvertown Tunnel, or stop it altogether”. Both Newham and Greenwich councils have called for the project to be paused and reviewed.

The tunnelling machine is the largest of its kind to be used in the UK, and part of the shield and the 250-tonne main drive have now been lowered into place. It will be named Jill, after Jill Viner, who became London’s first woman bus driver in 1974.

Juan Angel Martinez, the Riverlinx project director, said: “It gives me and the whole team an enormous sense of pride to have reached this important milestone for the Silvertown Tunnel project. Tradition states that the machines must be officially named before they can start work – and, as the patron saint of miners and tunnellers is Saint Barbara, they are given female names, our TBM will be named ‘Jill’.”

Helen Wright, Transport for London’s head of delivery for the tunnel, said: “The start of final assembly of the TBM within the launch chamber is a major milestone for the Silvertown Tunnel project as we prepare for the start of tunnelling later this year. I’m delighted that we will be naming the TBM after Jill Viner – a fitting name given how the tunnel will radically improve bus access across the river at this location.”

Health experts recently wrote to Khan asking him to pause the project, so modelling of traffic, emissions and air pollution can be updated, a new health assessment carried out, and the impact on London’s climate change targets reviewed.

Earlier this month the London Assembly called for Khan and TfL to provide data on what would happen if a future mayor dropped tolls on the Silvertown Tunnel in a motion opposed by Labour assembly members, despite the doubts about the scheme expressed by Newham and Greenwich, which are run by their party.