A leading figure in British sport has warned against importing athletes from overseas to boost the home medals tally at the London 2012 Olympics.

The British Olympic Association (BOA) has targeted fourth place in the 2012 medals table which would represent a big leap from the 10th place achieved in Athens four years ago.

However, Michele Verroken, the former director of ethics and anti-doping at UK Sport, says that lofty target should not be pursued at any price.

"Importing athletes from other countries to strengthen the medals chance in a sport is not a new phenomenon," Verroken told Web site www.insidethegames.com.

"What will cause an unease, are the implications that the UK - driven by the pressures to succeed in 2012 and to justify the expenditure of millions in the name of sport - could become a sporting nation willing to acquire medals by any means.

"It calls into question the real value of representing your country. Do athletes simply look around for a country with a lower level of athlete performance, desperate to achieve, offering better opportunities?"

Her comments come after reports last week that wrestlers from Ukraine and Bulgaria had been recruited by coaches working with the British team. They could qualify for a British passport by the time of the 2012 Olympics.

British tennis and the England cricket team has recruited overseas talent in the past while former Tongan rugby league convert Lesley Vainikolo made his debut for England in the Six Nations last weekend.

In the Olympics the most high profile case of an athlete switching to Team GB was middle-distance runner Zola Budd who controversially took British citizenship in 1984 to enable her to compete in the Los Angeles Olympics as her home nation South Africa was excluded from international sport.

While the circumstances of Budd's inclusion in the British team were unique at the time, Verroken is worried that future trends could see the emergence of a "transfer market" of Olympic medal hopefuls.

"Sporting nationality exchange could devalue the whole basis of international sport, turning the period between Olympic Games into a huge bidding and shopping market," she said.

However, the BOA says athletes would not be allowed to compete for Britain in an Olympics without sound personal reasons for changing nationality.

"The BOA has made it very clear some time ago, when I met individually with all the governing bodies, that we would only accept a change of nationality where there was a clear lifestyle change with the individual," BOA chief executive Simon Clegg was quoted as saying in the Daily Telegraph.

"We wouldn't support changes of nationality simply for convenience."