The second of two tunnels beneath the Thames - which together will form London’s new Silvertown Tunnel - is now complete.
Transport for London (TfL) confirmed that the project’s main tunnelling works have finished, after photos taken from the nearby IFS Cloud cable car - showing the tunnel boring machine on the north bank of the river - were shared with the Standard.
The machine - named ‘Jill’, after London’s first female bus driver - completed the first tunnel when it reached the river’s south bank in February. It was then rotated to make a return journey to the north bank, drilling the second tunnel in the process.
The 1.4km twin-bore road tunnel will link Silvertown, in Newham, with the Greenwich Peninsula, close to the O2 Arena.
The project has been controversial, with opponents arguing it will increase carbon emissions and worsen air quality and traffic.
TfL says the scheme will address the queuing and delays at Blackwall Tunnel, as well as provide a route for cross-river zero emission buses - and it says the project will reduce pollution.
In July, plans were unveiled for a ‘bike bus’ to transport cyclists through the tunnel.
The “bespoke” shuttle bus could run every 10 minutes and would only carry cyclists and their bikes, which would either be loaded onto the bus or a trailer pulled behind the bus.
The photos of the complete second borehole were taken on Thursday last week by Siân Berry, a Green member of the London Assembly.
Ms Berry - who believes the scheme will increase car dependency and risk new traffic and pollution - previously authored a report which proposed several alternative uses for the tunnel, including a tram system or an extension to the Docklands Light Railway (DLR).
This week, she called on mayor Sadiq Khan to “make this real blot on his record turn into something more positive”.
She added: “There are options for being very creative about how we use [the] Silvertown [Tunnel] in different ways to support public transport, walking and cycling, and not increase the traffic.”
Helen Wright, head of the Silvertown Tunnel programme at TfL, confirmed the main tunnelling works at Silvertown were a complete.
“We remain committed to delivering this project with minimal impact to those living, working and visiting the local area and the project remains on target to be completed in 2025,” she said.
TfL said it also remains committed to delivering an overall improvement in air quality as a result of the scheme, and that drivers will be subject to a user charge when it opens.
Mr Khan has in the past defended the Silvertown Tunnel.
"The east of London has been neglected for centuries," he told BBC last year.
"You have got 18 river crossings looking west from Tower Bridge, only one looking east.
"We are trying to make sure there is a new crossing which will have a lane reserved for double-decker buses to improve public transport.
"And it will be in the Ultra Low Emission Zone, so the air afterwards will be cleaner than it is now - that's a win-win."