The Queen has opened a transformed St Pancras station and new Channel Tunnel rail terminal for Eurostar.
Her Majesty said the £800m St Pancras International was "magnificent", and hoped people would consider it as not just a station but as "a destination".
Developers have called it the jewel in the crown of a £5.8bn project to bring high speed rail to the UK.
St Pancras will house high-speed services to Kent, Midland Mainline, Thameslink and six Tube lines.
Accompanied by the Duke of Edinburgh, the Queen offered her "warmest congratulations" to all those involved in the renovation.
She told guests the high speed rail service, known as High Speed 1, would make a "real difference" to people's lives and bring the UK closer to Europe.
The Queen said: "The remarkable re-birth of this great and gleaming station means that people across the whole of Britain, not just the South East, are suddenly quite a bit closer to Europe.
"And as we look forward to the London Olympics in 2012, it is good to know that a journey from here to the new High Speed 1 station at Stratford will take spectators a mere seven minutes.
"It gives me great pleasure to officially launch High Speed 1, Britain's first high speed railway and to re-open this magnificent station, St Pancras International."
The work to refurbush the station has taken 10 years
The evening ceremony was compered by actor Timothy West playing St Pancras' designer William Barlow.
The event saw two Eurostar trains and a Hitachi Bullet Train, which will shuttle spectators to and from the 2012 Olympic Park, arriving at St Pancras.
A suspended giant screen featured appearances from F1 driver David Coulthard, actress Kristin Scott Thomas and other personalities.
The Royal Philharmonic Orchestra, mezzo-soprano Katherine Jenkins and pop singer Lemar provided musical entertainment.
The 68-mile high speed railway line runs from St Pancras to the Channel Tunnel opening at Folkestone in Kent.
Work on the station began in 2001 to enable it to accommodate domestic rail services and Eurostar trains to and from France and Belgium.
The front of the station, Sir George Gilbert Scott's neo-Gothic building, will open as a five-star hotel in 2009.
The new route will cut journey times to Paris by 20 minutes to two hours and 15 minutes, and to Brussels by 25 minutes to one hour and 51 minutes.