A handful of Eurostar trains call at Calais-Frthun, a few miles from Calais town centre, but others just start accelerating onto the French high speed line.Unlike conventional railways, the high speed line follows the contours of the land more like a motorway, and you will feel the Eurostar rising onto the hills and settling into the dips.To the left of the train, over the top of the adjacent M2 motorway bridge, you can see Rochester Cathedral and Rochester Castle in the distance.Now at last you're in green and pleasant rural Kent, with villages nestling at the foot of the chalky hills to the left.Just 10-12 minutes from St Pancras you'll see the impressive Queen Elizabeth II suspension bridge on the right, which carries the M25 London orbital motorway across the River Thames at the Dartford Crossing.The Eurostar now plunges back into a short tunnel for its own crossing underneath the Thames, emerging the other side in the county of Kent.Some Eurostar trains now call at Ebbsfleet station in north Kent, near the M25 motorway.

They were refurbished with an interior by designer Philippe Starck in 2004-2005.

As a precaution, the yellow fire safety doors between each pair of coaches are closed during the tunnel transit, but you can still pass through freely if you want.

You still get phone reception inside the tunnel now, with mobile data too.

A few Eurostars still call at Ashford International station, a major railway junction in east Kent, but most Eurostars now 'fly' over the town on a huge flyover, with the station way below you, the town centre to the left and the old Southern Railway Ashford works to your right.

Just 35 minutes from St Pancras, the fields and hedgerows of east Kent give way to the roadways and check-in lanes of the Folkestone Eurotunnel terminal.