The organisations are working in close partnership with rowing, handball and volleyball.

The major new appeal was launched in Trafalgar Square, with Sir Steve Redgrave among the stars helping to put potential athletes through their paces.

On the back of it, UK Sport is aiming to encourage individuals between the ages of 16 and 25, with good all-round athletic ability, to submit an application via its website. The starting point is that they are 5ft 11in  (180cm) or above if they are female, or males taller than 6ft 3in (190cm).

The initial application form can be found at www.uksport.gov.uk/talent and should be completed no later than Friday March 23.

Those that make it through the initial screening will then be invited to a series of sport specific Talent Identification screenings which will commence by the end of March.

Speaking at the launch, Chelsea Warr, UK Sport's performance consultant said:  "With just five and a half years to go, the race is on to unearth some hidden talent of the 6 foot plus variety.

"We have a unique opportunity to pluck individuals from relative sporting obscurity and provide the opportunity of a sporting lifetime.

"Put simply, if you're exceptionally tall, a good all-round athlete and have the 'right stuff', it could be you!

"Becoming an Olympic athlete is one of the hardest journeys that sport has to offer, but with London 2012 on the horizon the opportunities are immense.

"We are looking for people who possess the right talent characteristics to take up the challenge.

"Following an initial shortlisting, the selected few will be invited to undertake a more detailed investigation by the sports, together with leading talent identification specialists.

"We'll be looking for those that can demonstrate that they have the full talent package required to stand up to the rigours of life in elite sport."

The opportunity has come about as two of the newer team sports to the UK's high-performance system look to kick start their Olympic campaigns with an injection of new talent to complement their existing squads.

At the same time, GB Rowing is looking to sharpen its increasingly successful women's talent identification programme (backed by National Lottery funding and now sponsored by Siemens) - which has already produced world championship finalists including talented young athletes like Anna Bebington and Annie Vernon in as little as four years - with some new recruits.

With the sports looking for potential athletes with similar characteristics, UK Sport has taken the opportunity to coordinate the drive for fresh blood.

Sports Minister Richard Caborn enthusiastically welcomed the initiative.

"Sporting Giants will give taller athletes the chance to reach the peak of their potential by trying sports both new and old, introducing them to the high-performance environment," he said.

"The home crowd will want to see the best of British talent when London hosts the Olympic Games in 2012. This campaign will help us to meet those high expectations."

UK Sport is citing the examples of Japan, who moved from 15th to fifth in the Olympic medal table between the Sydney and Athens Games, largely as a result of a targeted and systematic talent identification programmes, and South Korea, who in the lead up to Seoul 1988 populated medal winning teams in handball (won gold and silver medals) and hockey (silver) with ready-made athletes transferred from other sports, as examples of where such a system has previously worked.

Once applications have been submitted to UK Sport, the athletes' profiles will be scrutinised by a multi-disciplinary team of experts including the respective sport's elite coaches and sports scientists from the EIS and UK Sport.

If successful, applicants will pass through an initial sport specific screening stage where their 'trainability' and suitability will be put under the microscope. This auditioning process will continue with further shortlisting until people with all the 'right stuff' are identified.

"Life as an Olympic athlete is incredibly tough," said Warr.

"If you are to take on and live with the best in the world, you will have to work harder than you ever magined possible and make significant sacrifices.

"Statistics show that typically around one per cent of those that set out to become an Olympian actually make it.

"But in order to maximise our chances ahead of London 2012, we're asking people to take on that challenge and it can start here today, simply by visiting our website."