 This route has the greatest strategic advantage, as the Chiltern Main Line is a popular alternative to the WCML from Birmingham to London, and also lends the opportunity to build a branch line to Heathrow Airport, giving the passengers served by the WCML a direct service to one of the world's premier international airports.The WCML is also the corridor which would be under the most pressure in the next 15 – 20 years.A connection to High Speed 1 would allow Eurostar terminals to open in Birmingham and Manchester.