By Duncan Mackay at Trafalgar Square in London

July 27 - The medals to be awarded to the winners at next year's Olympics were unveiled here tonight by the Princess Royal and Sebastian Coe in the presence of Jacques Rogge, the President of the International Olympic Committee (IOC).

They have been designed by British artist David Watkins and will be made by the Royal Mint in Wales.

"Highlighting the effort and achievement of the athletes, as well as the city where the Games are held, these beautiful medals will be a fitting reward for the Olympic medallists of 2012," said Rogge.

"It is the pinnacle of a sporting career to become an Olympic champion but I am confident that receiving one of these medals will make it all the more special in London next year.

"Congratulations to LOCOG for creating a design that will inspire the Olympians of 2012."

Watkins, who had been the special effects modelmaker on the hit movie "2001 - A Space Odyssey", was chosen to design the medals from a shortlist of six who had whittled down the 100 artists who had applied for one of the most prestigious roles at the Games.

"It is exciting to think that the finest athletes in the world will be wearing my medal design next summer," said Watkins.

"Its key symbols juxtapose, front and back, the goddess Nike for the spirit and tradition of the Games, and the River Thames for the city of London.

"I hope the medal will be enjoyed and treasured as a record of great personal achievements in 2012."

The Olympic medals' circular form is a metaphor for the world while the front always depicts the same imagery at the summer Games - the Greek Goddess of Victory, Nike, stepping out of the depiction of the Parthenon to arrive in the Host City.

The back features the contorversial London 2012 logo while the core emblem is an architectural expression, a metaphor for the modern City, or as a geological metaphor as a tough crystalline growth which is deliberately jewel like, Watkins explained.

The grid brings both a pulling together and sense of outreach on the design - an image of radiating energy that represents the athletes' achievements and effort, he said.

The River Thames is a symbol for London and also suggests a fluttering baroque ribbon and adds a sense of celebration.

The square is the final balancing motif of the design, opposing the overall circularity of the design and emphasising its focus on the centre and reinforcing the sense of 'place' as in a map inset.

The sport and discipline of the medal-winning athletes will be engraved on the rim of every medal.

In 2012 more than 2,100 Olympic medals will be presented in 302 Olympic victory ceremonies in more than 30 venues over 16 days of competition.

"I hope that seeing the design of the London 2012 Olympic medals will be a source of inspiration for the thousands of athletes around the world who are counting down the year before they compete at the greatest show on earth," said Coe.

"All of our preparations are focused on ensuring the athletes are at the heart of the Games, and I believe that through this rigorous process the panel of experts have selected an artist and a design for medals that all athletes would be proud to own."

Watkins, 61, a former professor at the Royal College of Art, was chosen by an independent panel chaired by Sir John Sorrell with Paralympic bronze medallist Ade Adepitan as his deputy and which also consisted of Iwona Blazwick, the director of the Whitechapel Gallery, Sir Mark Jones, the Victoria & Albert director and amedals expert, writer Catherine Johnson and Martin Green, the London 2012 head of ceremonies.

London 2012 also worked closely with the British Museum's Keeper of Coins and Medals, Philip Attwood, to look at the symbolic history of medals in Europe in the last century and in particular medals that held stories that travelled symbolically from the front of the medal to the back.

The London 2012 Athletes' Commission, chaired by former Olympic triple jump champion Jonathan Edwards (pictured with Watkins), were also closely consulted.

Each medal will weigh 375-400g, be 85mm in diameter and 7mm thick.

The gold medal is made up of 92.5 per cent silver, 1.34 per cent gold with the remainder copper.

There is a minimum of 6g of gold, as stipulated by the IOC.

The ore for the medals is supplied by London 2012 sponsor Rio Tinto and is mined at Rio Tinto's Kennecott Utah Copper Mine near Salt Lake City in America, as well as from the Oyu Tolgoi project in Mongolia.

The medals will go into production later this year at Royal Mint's headquarters in Llantrisant, South Wales.

"The design is dynamic, full of energy and makes ingenious use of the 2012 symbol," said Sir John.

"It is a beautiful piece of craftsmanship with a crystalline, jewel-like quality."