London transport: First look inside £2.2bn Silvertown Tunnel

TfL's director for investment planning, David Rowe, says a key target is to reduce overall pollution and they will do that through tolls.

"A fundamental objective around the Silvertown Tunnel is addressing the problems we have at Blackwall," he said.

"At the moment are sitting in traffic for 20 minutes in park periods trying to queue to get across the river as it's the only strategic crossing.

"So if Blackwall goes down and we have to shut it 700 times a year, there's a significant spread of traffic and that obviously leads to worse air quality conditions.

"With the Silvertown tunnel in place, we get rid of the queueing, we solve the air quality problems.

"Our assessments have shown there's an overall improvement in air quality and we are committed to delivering that."

He says the toll will stop an increase in traffic.

"Importantly a key part of the scheme is the introduction of new cross river bus services and they offer a viable alternative for those wanting to cross the river.

"It won't lead to more traffic as the user charge which is also part of it will ensure that we don't attract any more traffic into London."