Company charged with proposing high speed line factors in Conservative success in next general election

The company examining the case for a high speed rail link from London to Birmingham is taking into account the Conservatives' pledge that an extension to Heathrow will not be built.

In an interview with the Guardian, the chairman and chief engineer of High Speed Two said they needed to keep all options open when drawing up proposals for a future government.

The report models Heathrow with and without a third runway, so that it will be useful to whichever party wins the next general election. The first phase would see a £7bn high speed rail link built from London to Birmingham via Heathrow.

Andrew McNaughton, High Speed Two's chief engineer, told the newspaper that high speed rail in the 21st century would be as important to the UK as motorway-building in the 20th century.