Mayor of London Boris Johnson has sparked anger on Twitter after confirming a new "Dartford 2" crossing over the River Thames.

In an online question and answer session, entitled #askBoris, the Conservative was asked by Twitter user Mark Bailey "when will there be another tunnel/bridge built to ease traffic at dartford and Blackwall tunnels".

And his reply was: "yes the new silvertown crossing will be in by 2020 followed by 3 more bridges inc Dartford 2".

The response on Friday drew an instant reaction from users.

Phil Rogers tweeted: "you're confirming a new bridge at Dartford?!"

While Elaine Willis posted: "and we will pay for ever like the Dartford one despite all the promises !"

Derek Murray replied: "Dartford 2"? The Thames need more crossings. Dartford most certainly doesn't."

In October, a think tank led by former transport minister Lord Adonis recommended a new Thames crossing should be built near to the existing Dartford bridge.

It is one of four new river crossings recommended in a report by the Commission on East Thames Crossings, which it says could kickstart regeneration in the Thames Gateway area.

The recommendation comes as the Government continues to draw up detailed plans for a new Lower Thames Crossing at one of two locations, including next to the QEII Bridge in Dartford, known as Option A.

The other would cut through woodland and villages east of Gravesend, known as Option C.