Everything you need to know about the Blackwall Tunnel

But what is the Blackwall Tunnel? And what do you need to know if you’re going to be using it on your next road trip?

To help put any concerns you might have to rest, here’s our guide to everything you need to know about the Blackwall Tunnel.

Guide contents

• What is the Blackwall Tunnel?
• Where is the Blackwall Tunnel?
• Is there a toll for the Blackwall Tunnel?
• Blackwall Tunnel traffic
• Is the Blackwall Tunnel open?
• What’s the closest alternative Thames crossing?
• Is there a height restriction for the Blackwall Tunnel?
• What’s the speed limit in the Blackwall Tunnel?
• Why is the Blackwall Tunnel curved?
• Will there be a third Blackwall Tunnel?

What is the Blackwall Tunnel?

The Blackwall Tunnel is actually two separate tunnels that travel beneath the Thames in east London — one tunnel for southbound traffic and the other for northbound traffic.

The original Blackwall Tunnel was officially opened by the then Prince of Wales on 22 May 1897 as a £1.4m project aimed at improving trade and commerce in and around London’s East End and the nearby docklands.  

Originally used by horse-drawn carts, cyclists, and pedestrians, as vehicular traffic grew so did congestion in the tunnel, forcing authorities to build a second Blackwall Tunnel, which opened to the public in 1967.

The original tunnel now supports northbound traffic, while the newer tunnel acts as a southbound route, with all non-motorised traffic now banned from using the tunnels in favour of car traffic.  

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Where is the Blackwall Tunnel?

The Blackwall Tunnel travels underneath the River Thames in east London, connecting Poplar and the Essex-bound A12 in the north to North Greenwich and the Kent-bound A2 in the south.

The Tunnel itself forms part of the A102, with the southbound tunnel passing underneath the O2 — formerly known as the Millennium Dome — as it travels below the river slightly downstream from its northbound neighbour.

Despite various stalled plans to build another Thames crossing, the Blackwall Tunnel remains the most easterly free road crossing on the river, with only the Dartford Crossing (toll) and the Woolwich Ferry further east.

Is there a toll for the Blackwall Tunnel?

No, there’s currently no toll for the Blackwall Tunnel. However, motorists often get the Blackwall Tunnel confused with the Dartford Crossing further downstream, which does have a toll - the Dart Charge.

Blackwall Tunnel traffic

Unsurprisingly, the Blackwall Tunnel is busiest during the morning and evening rush hours, however TFL data shows that there are differences between the two tunnels.

The northbound tunnel is busiest during the morning rush hour— between 06.30 and 08.30, while the southbound tunnel sees most traffic in the evening rush hour, from 16.00 to 18.00. Drivers can be held up for 20 minutes or more during busy times.

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Is the Blackwall Tunnel open?

The tunnel is open and toll-free 24 hours a day, unless the authorities have concerns over driver safety in the event of a fire, crash, or an unauthorised road user using the tunnels.

However, the tunnels are regularly closed for routine maintenance works, with these works usually happening at quieter times such as overnight or over the weekend.

If you’re intending to use the Blackwall Tunnel but it’s closed, you’ll need to find an alternative route to cross the Thames so check the RAC Route Planner for the latest up-to-date traffic news to rearrange your journey.

What’s the closest alternative Thames crossing?

While you might think of the Thames being criss-crossed by bridges as it passes through London, there are actually very few river crossings in east London which is why the Blackwall Tunnel is such an important route.

The nearest vehicular river crossings to the Blackwall Tunnel are the Rotherhithe Tunnel two miles to the west and the Woolwich Ferry two miles to the east, although the ferry does not run overnight.

Further afield, Tower Bridge is located three miles to the west while the Dartford Crossing is 16 miles to the east of the Blackwall Tunnel, although there is toll to use the Crossing.

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Is there a height restriction for the Blackwall Tunnel?

The Blackwall Tunnel has a height restriction of 4m (13'0”) northbound, 4.7m (15'6”) southbound, so ensure that your vehicle can safely navigate the tunnel before making your journey.

It is an offence to ignore a height restriction sign, and you could be hit with a Fixed Penalty Notice of a £60 fine and three points on your licence if you’re caught ignoring the signs.

What’s the speed limit in the Blackwall Tunnel?

The speed limit is 30mph or 48km/h.

Why is the Blackwall Tunnel curved?

If you’ve ever driven through the Blackwall Tunnel, you’ll notice that the tunnel has several sharp bends so it could align with Northumberland Wharf to the north and Ordnance Wharf to the south, as well as avoiding a nearby sewer.

Another reason for the curved tunnel is due to the fact that the main mode of transport when it opened was horse and cart, so the tunnel had to be curved to avoid the horses seeing daylight at the end of the tunnel and bolting towards it.

Will there be a third Blackwall Tunnel?

Due to congestion and the need for occasional closures for routine maintenance, a third bore of the tunnel was proposed in 1989 by Cecil Parkinson – the then Transport Secretary.

The third tunnel never made it off the drawing board due to logistic issues, but the idea of a new Thames crossing in east London has been discussed for many years, with plans approved in May 2018 for the Silvertown Tunnel

The new link, which could be open as early as 2024, would connect the Royal Docks north of the river to North Greenwich in the south, linking up near the southern entrance of the Blackwall Tunnel.