Gatwick Airport has announced a raft of transport improvements designed to make it "road and rail ready" for a second runway by 2021.

The airport will run a train to central London every 2.5 minutes by 2019, in addition to doubling its rail capacity by 2020 and nearly trebling it by 2035. New Gatwick express service trains will be introduced by 2016.

Upgrades are also planned for the  M25 and M23, including the introduction smart motorway use with hard shoulder running.

As a result of the infrastructure improvements, some 15 million people will be brought within 60 minutes of Gatwick - more than any UK airport.

Hugh Sumner, senior transport advisor for London Gatwick, said: "Gatwick already has the highest proportion of passengers travelling by public transport and these improvements will help encourage even more."

He added that Gatwick aims to ensure 60 per cent of its customers use public transport, which would place it first in the UK for public transport use.