Silverstone has unveiled its new multi-million pound pits and paddock complex, two months ahead of its flagship event, the British Grand Prix, on 10 July.
After striking a new 17-year deal to host the race, the British Racing Drivers' Club (BRDC), which owns the circuit, agreed to the redevelopment.
The upgraded Silverstone 'Wing' has cost £27m.
"There was a real threat the grand prix would go," said BRDC president Damon Hill. "So this is very important."
Hill was one of five British world champions alongside John Surtees, Sir Jackie Stewart, Nigel Mansell and Jenson Button, who attended the opening of the new facility.
Mansell, winner at Silverstone three times in the British Grand Prix, said: "This track is the best in the world for me bar none. The crowd gets behind the driver if there's a sniff of a win."
Button, who is determined to end his winless streak on home soil with McLaren this season, agreed that driving at Silverstone was a thrilling experience.
"It was pretty emotional coming here as a world champion," said Button, who won the title in 2009.
"Even through the difficult times for a British driver you get so much support here. It would mean so much to win here."
Silverstone first staged the British Grand Prix in 1948 and the former airfield in Northamptonshire has undergone a major facelift after securing the rights to hold the race until 2027.
That deal was struck after a proposed move to Donington Park fell through because of a lack of funding but Formula 1 supremo Bernie Ecclestone warned that a revamp of Silverstone's pit building was a non-negotiable part of the agreement.
Ecclestone has always expected more from Silverstone, once describing the British Grand Prix as "a country fair masquerading as a world event".
The 80-year-old Ecclestone was unable to attend the ceremony but sent a message of congratulations.
"I'm delighted with the progress and prospects for the future of Silverstone," Ecclestone's statement said.
"The pits and paddock complex is a state-of-the-art facility and will form the backbone of Silverstone's plans to be a world-class facility.
"It's a great shame it couldn't be completed 10 years ago but well done."
Hill added: "Bernie has acknowledged that Silverstone has come up to the requirement that he stipulated.
"So much of this is the way it is because it is the way Bernie wanted it."
The towering three-storey pit complex has been designed by the architects - Populous - behind the London 2012 Olympic stadium.
It includes 41 garages, the race control building and podium, hospitality suites, a media centre and a new spectator area towards the end of the lap.
Silverstone's transformation began in 2010 with the introduction of a new layout which blended a series of corners after Abbey before rejoining the old track at Brooklands and lengthened the track by almost half a mile.
Now the start-finish line, in use for the F1 race and June's MotoGP event, has been moved between Club and Abbey corners.
The relocation of the start-line could alter the racing, with the competitors flowing into Abbey's fast first corner.
The first F1 car to get a taste of the new pits was Mark Webber's Red Bull which roared into the opening ceremony setting the assembled guests' ears ringing.
Webber took the chequered flag at Silverstone last season and when he emerged from the cockpit the Australian commented: "It's an absolute no-brainer to hold the event here."
The new facility, which is 390m in length and 30m high, was officially opened by the BRDC president in chief, His Royal Highness The Duke of Kent, who praised the "dedication" of the club's members.
The opening of the 'Wing' is just the first phase of Silverstone's continued redevelopment as the BRDC is now focused on providing better facilities for British motorsport fans, such as the building of more permanent grandstands.
"We've got big plans and this is just the beginning," added managing director Richard Phillips."