Boris Johnson proposes underground roads during Boston visit

The London mayor has announced plans to redesign some of London's busiest roads by taking stretches of them underground.

The idea to replace wide stretches of roads and flyovers with tunnels has been proposed by Boris Johnson, who is on a trade visit to the US.

While in Boston, where a similar project has been completed, he said the scheme could release "a huge amount of land that could be turned into a park, several parks, and other amenities, plus releasing a lot of land for housing".

BBC London's political correspondent Karl Mercer reports from Boston, where he spoke to local historian Karen Connors, Mr Johnson and coach driver Joe Bordonaro.