FIRST the "Plastic Brits".

Now for the "Plastic Scots." And who better to identify them than a man cast from that very mould – Sean Lineen, Scottish rugby's first Kilted Kiwi. We had the irony of Australian Matt Williams, first foreigner to coach the national rugby team, introducing a

"Fortress Scotland" philosophy – only those playing on home soil could play for the national team. Now, just a few years on, Lineen is to trawl the globe for players qualified to represent Scotland.

He once told me during a light-hearted conversation on allegiance: "There are two types of people – those who are Scots, and those who would like to be Scots." By his own admission, Lineen was not good enough to be chosen as an All-Black, but grasped the thistle thanks to the serendipitous discovery of a grandfather from Lewis.

The likeable Lineen, still, tellingly, in Scotland after 23 years, will tread a minefield as he checks potential eligibility – think David Hilton and Steven Shingler. Hilton discovered after 41 Scottish caps that his grandfather was English, not Scottish. Shingler was named for this year's Six Nations squad on the strength of a mother from Dumfries, but had represented Wales Under-20s 14 times. Both were embarrassingly ruled unselectable by Scotland.

Eligibility is a complex issue and we should not rush to judgment. Career (mercenary?) and nationalist considerations are not the only forces at play. Though lottery resources lure numerous carpetbaggers to these shores, it's not one-way traffic. Notoriously, it prompted the defection to England of Scotland's former world squash No.1, Peter Nicol.

Sports flags of convenience denote an industry populated by economic migrants.

Numerous countries' table tennis and badminton teams are loaded with Chinese who would never get near the People's Republic team. At the Pan Arab Games in Doha last year, it was an open secret that the Qatar basketball team avoided interviews because none spoke Arabic.

Yamile Aldama, Cuban by birth, married to a Scot, won World Indoor Championship triple-jump gold in Istanbul on Sunday, breaking the UK record. She had won World Indoor silver for Cuba in 1999, but on moving to the UK, they would no longer select her. When her husband was jailed for drug trafficking, her GB passport was delayed, though she was an innocent party. Stateless, she accepted a Sudanese passport and rewarded them with World Indoor silver and bronze.

Renunited with her now-liberated husband, mother of two sons born in Britain, she has been resident in London and coaching kids there for more than a decade. At 39, she is an Olympic title contender. She is also a potential GB athletics team captain, according to Britain's head coach, Dutchman Charles Van Commenee.

He gave that honour to Tiffany Porter at the weekend. An American with an English mother, she was invited by the Daily Mail to recite God Save The Queen. She declined, and the tabloid was banned from further press conferences. Porter, who set a British record last year, won silver in Istanbul.

The media double standards and hypocrisy are worthy of a gold medal. This is the paper which arranged for the original plastic Brit, Zola Budd, to be fast-tracked to a UK passport in just 13 days in 1984.

Van Commenee's trailing of Aldama for the captaincy may simply be another two fingers to that journal, but given her inspirational performance in adversity, he could do worse.

The GB gold-medal 4 x 400m quartet in Istanbul included Shana Cox, born in Hicksville, USA (really!), while another dual-nationality athlete born in the US, Michael Bingham, was part of the men's silver-medal squad. Shara Proctor, who broke the UK long jump record to take bronze, has switched allegiance from Anguilla. It is a British overseas territory but has no National Olympic Committee, so to compete in the Games she has to use her British passport. She first set foot in the UK when she ran at the Kelvin Hall last year.

English cricket has its foreign legion. Former captain Mike Denness was Scottish. More recent players such as Allan Lamb, Kevin Pietersen and Andrew Strauss, were all born in South Africa. Just yesterday, England's 2005 Ashes Test wicketkeeper, Geraint Jones, played for Papua New Guinea (he was born there) in a World Twenty20 qualifier against Afghanistan.

Scottish team sports' lack of critical mass may, indeed, be a compelling reason for searches like that on which Lineen is about to embark. But consider this. A sport reliant on imported talent is built on sand. Long ago, David Murray tried to buy basketball success in Scotland, with Murray International Metals. It failed – a combination of lack of domestic tradition, fan base, home-grown players or role models, but also because it was built on imports and sustained by the depth of his pocket.

Rangers are now paying the price for his injudicious grafting of a similar policy on to football. There's an argument that the national football team's enduring mediocrity is a partial consequence of a byproduct – reduced opportunity for domestic players.

Rugby flourishes in New Zealand (and Wales) thanks to tradition, fan base, a high-level domestic game, and inspiring home role models. Football in Scotland once flourished internationally due to the same factors, but no longer.

We wish Lineen well, but buying success, and medals, is false economy. Britain's successful sports are rowing, sailing, cycling, swimming. I can't name an in-comer.