by Jo Sword and business editor Trevor Sturgess

The full high-speed rail service got under way today with Prime Minister Gordon Brown calling it "a momentous day in the glorious history of British railways".

The PM was at St Pancras International in London to meet the 7.07am from Rochester on Monday.

He greeted VIPs, Kent Olympian Dame Kelly Holmes, Transport Secretary Lord Adonis, Gillingham MP Paul Clark and Gwyn Prosser, MP for Dover and Deal.

Mr Brown said: "This is a great day for St Pancras, a great day for Kent and a great day for rail services in this region. Today is a momentous day in the glorious history of British railways."

KM Group reporter Luke Hollands was on the train and described a "carnival atmosphere". He added: "Everyone is thrilled that such a great service has come to our county."

The train 001 was named after Dame Kelly, pictured above chatting to Mr Clark on the train. Other Kent Olympians Jamie Staff and Steve Backley also have trains named after them.

Dame Kelly said it was brilliant to have a train named after her. "The quality of life for people in Kent will be fantastic, it's really cutting down these travel times."

Mr Clark, who is also transport minister, called it an historic day.

Lord Adonis said: "This is a transformation moment for Kent, not only because it's the fastest service Kent has ever seen but also because of the regeneration effects that will come from transformed transport connections between east Kent, the Medway towns and London."

In June, the preview service from Ashford to London St Pancras was launched, with services to Dover and Ramsgate following in September.

The Javelin trains speed through the Kent countryside at 140mph, dramatically cutting journey times to the capital.

Mr Brown added: "This is the key infrastructure that will help businessses and communities flourish and deliver generation. I hope this will be a blueprint for the future of high speed rail travel in the UK."

Jon Hay-Campbell from Southeastern Trains said: "We have been very pleased with how the preview services have been going and we have seen a steady growth over the weeks and months since we introduced it back in June.

"The services have seen passenger numbers rise up to almost 23,000 journeys every week."

However, all this comes at a price - with passengers being asked to pay more and standard services in west Kent being cut.

Jon Hay-Campbell from Southeastern said: "There are those such as those from Maidstone East and West Malling where they will see a reduction and we are going to continue to monitor the service from January.

"Once it has come into effect properly and we will look to see how we can improve it."