London Underground (LU) announced it is looking for suppliers to help create its vision for the future.

Under the proposals, trains could become fully-automated, while the introduction of air-controlled carriages would make journeys more pleasant for passengers. The new initiative will run on the Bakerloo, Central, Piccadilly and Waterloo and City lines. 

Around 250 new trains will be brought into operation as part of the project, which is aimed at helping the capital cope with an expected surge in demand for the service. This is due to estimations London's population will increase by almost two million by 2030.

Mayor Boris Johnson commented: "This is a hugely important step in the continued evolution of our world-famous Tube and one that will see an iconic new fleet of trains to keep London and its economy moving."

LU intends to place a notice with the Official Journal of the European Union to seek expressions of interest for the new project. It expects to issue invitations to tender by early next year.