Olympic triple gold medallist Chris Hoy today unveiled the design for London's VeloPark, where Britain's cyclists aim to recreate their Beijing success.

The 2012 venue, at the north of the Olympic Park, will include a 6,000-seat velodrome and 400 metre BMX circuit.

Underneath a spectacular "floating" roof will be a glazed concourse, offering views of London's skyline.

The building has been designed by Hopkins Architects, who say it is intended to be lightweight and efficient - reflecting the workings of a bicycle. The venue will also be linked to cycle routes across the capital.

The £80 million budget, one of the Olympic Park's largest, now dwarfs the original bid figure of £28 million.

Olympics chiefs say the concept has since been expanded to house a one-mile road cycle circuit and 6km mountain bike course.

These facilities, to be created after the Games, will form part of the 2012 legacy, catering for cyclists of all abilities. A spokesman for the Olympic Delivery Authority said: "The current budget is for a venue with a much wider range of facilities and the design now includes a road cycle circuit and a mountain bike track to be completed after 2012. It's about providing a permanent world-class cycling facility for London."

Hoy, the first Briton in 100 years to win three gold medals at the same Olympic Games, said he hoped the building would boost the popularity of cycling.

"Becoming Olympic champion simply wouldn't have been possible without the local cycling facilities I used when I was growing up, so I'm delighted to help launch the designs of the London 2012 VeloPark, which will provide first-class facilities for cyclists of all ages and abilities," he said.

The cyclist visited the site this morning with Boris Johnson, Lord Coe, chairman of Games organisers Locog, and ODA chief executive David Higgins. The Mayor said the venue would be an " outstanding iconic landmark"-adding: "I can't wait to see the finished structure packed to the rafters, cheering on Team GB cyclists as once again they go for gold in 2012."

The design team, which also includes Expedition Engineering, sustainability consultants BDSP and regeneration experts Grant Associates, was chosen last summer.

Their initial concept has been tweaked after consultation with local user groups and cycling experts.

The double-curved roof structure, to be clad in 288 exposed timber panels, reflects the geometry of the cycling track. A continuous ribbon of windows underneath will allow a view of the track from outside, and offer spectators-inside a vista of the rest of the Olympic Park.

To make the building as environmentally friendly as possible the design uses daylight to reduce electric lighting and allows natural ventilation. Water saving fittings allow the collection of rainwater for use inside.

Construction is due to begin next spring by builders ISG.

The release of the plans follows the opening of the £4.5 million Redbridge Cycling Centre last month. This replaced the Eastway Cycle Circuit. which was demolished to make way for the Olympic venue.