Transport for London (TfL) has announced two weekend closures of the southbound Blackwall Tunnel.

The closures, which will take place across the weekends of July 20-22 and August 17-19, are required to support the opening of the new Silvertown Tunnel in 2025.

They will allow for the final road configuration to be implemented, as well as road resurfacing and safety barrier works to be carried out.

The dates, says TfL, have been chosen to avoid key events happening in London during the summer.

The Silvertown Tunnel opens in 2025 and will help reduce traffic congestion and deliver faster, more reliable journeys in east London.

Across the weekends, the Blackwall Tunnel will be closed for southbound traffic and drivers will need to take alternative routes.

Northbound traffic will not be affected by these closures as traffic will be diverted through the southbound Blackwall Tunnel when required.

The weekend closures will start at 12.01am on the Saturday morning, with southbound traffic being restored by 5am on the Monday morning at the latest.

Nick Fairholme, director of capital delivery for systems at TfL, said: “We are now in the final phase of works to complete the Silvertown Tunnel and these closures will help us to start to get the tunnel ready to open.

“We appreciate that these planned weekend works will have an impact on some drivers and are doing everything we can to limit potential disruption - including ensuring a northbound route through the Blackwall Tunnel is maintained throughout.”

Drivers are advised to plan their routes in advance, checking before they travel so they can consider any other potential traffic impacts or restrictions, such as the height and weight limits at Rotherhithe Tunnel and Tower Bridge, both of which are outside the Congestion Charge zone.

Roads and alternative river crossings in east and central London are expected to be extremely busy with traffic around Rotherhithe Tunnel and along the A13 Commercial Road between Canning Town and Whitechapel heavier than normal over the weekends due to the closures.

The Woolwich Ferry, which now departs every fifteen minutes, seven days a week, will be in operation across the weekends.

Where possible, people should consider using public transport or walking and cycling via other river crossings to complete their journey, says TfL.

Drivers of HGVs, as well as vans more than two metres in height or weighing more than two tonnes, are advised to consider routes away from central London across the weekends where possible.

To help inform drivers of the works, additional variable messaging signs will be placed on the main roads approaching the Blackwall Tunnel.

TfL has also worked with third party app providers, such as Waze, to help ensure drivers who regularly use the Blackwall Tunnel are alerted to the southbound closure and that the closure is shown in any route-planning over the weekend.

TfL will also take the opportunity to carry out works within and around the Blackwall tunnel, to help deliver future maintenance work more efficiently and ensure the tunnel can continue to safely operate.

Further information about the closures from TfL can be found here.