The power system that will carry high-speed trains through Kent on the Channel Tunnel Rail Link will be switched on for the first time on Saturday night.

Overhead wires along the first 46-mile section of the new railway will carry 25,000 volts of electricity from midnight.

The power will run between Fawkham Junction, near Swanley, and the Channel Tunnel at Cheriton.

Chris Jago, of Union Railways South, which is in charge of the first section, said it was an important milestone for the project.

Eurostar running

He said: "We have been getting ready to electrify the overhead wire, so a stretch that runs from the Channel Tunnel - roughly half the length of the route - is energised to 25,000 volts.

"This is just another stage towards the formal opening and the running of Eurostar trains at the end of September."

Signalling must be installed and the trains tested before the first section of track goes operational in the autumn.

The second section of track, due to be completed in 2006, will run to St Pancras, in London, completing the 68-mile link to the coast.