A massive project to build railway tunnels beneath the Chilterns today moved a step closer when engineers began assembling two giant drilling machines..
The 2,000-tonne boring machines will spend 3.5 years excavating 2.7m cubic metres of flint and chalk.
The two parallel tunnels will form part of the £106bn HS2 railway line from London to Birmingham and Manchester.
The German-built tunnelling machines named Florence and Cecille are being put together from hundreds of parts on a site next to the M25 in Buckinghamshire. Engineers likened it to a giant Meccano set.
Environmental activists trying to disrupt the project are occupying a makeshift bridge across the River Colne in nearby Denham Country Park.
Among the protesters was veteran environmentalist 'Swampy' who made his name campaigning in the 1990s.
He came to the public's attention after spending a week living in a network of tunnels to disrupt the extension to the A30 in Devon.