F or seasoned watchers of the comings and goings at the headquarters of Scottish rugby, there was a sense of weary familiarity about yesterday's gradual realisation that all might not be quite as it first seemed in the curious case of Steven Shingler's sudden arrival in the Scotland squad.

For the fact is that eligibility rows have been as regular a part of the Scottish scene as managerial meltdowns at Murrayfield. The antennae were twitching when that hilariously ironic advert showing Shingler donning the same shirt as Barry John and Phil Bennett popped up on YouTube, but it soon became clear that the player's background might not be a laughing matter after all.

Of course, the Welsh have particular reasons to be touchy about such things. Twelve years ago, they became embroiled in Grannygate, the most notorious eligibility scandal of modern times, when it was revealed that Shane Howarth and Brett Sinkinson, who had respectively won 19 and 20 Wales caps, had no Welsh qualifications at all.

In the immediate aftermath of that affair, the international credentials of prop Dave Hilton, a Scotland regular for the previous five years, were called into question. Initially, the SRU issued a tetchy rebuttal of the charge that he was ineligible to play for Scotland, but a few days later they were forced into a humiliating climbdown and made the admission that Hilton's claim that his grandfather was born in Edinburgh had no basis in truth whatsoever.

At that time, questions were also raised over the eligibility of Peter Walton and Budge Pountney, two regulars in the Scottish back row. Walton's 'qualification' to play for Scotland rested on the fact that he had spent a few years at Merchiston Castle school as a teenager; Pountney's was based on an imaginative reinterpretation of the football rule that allows players born in the Channel Island to opt for any one of the four home countries.

As it happened, Pountney had been born in Southampton, but his grandmother had been born in the Channel Islands. No problem, said the Scotland rugby authorities of the time. They borrowed the football rule (it had never applied in rugby), cast it back two generations and, hey presto, the Northampton flanker was suddenly a Scot.

There had also been the curious case of Alistair Murdoch and Paul Johnstone. Centre Murdoch had been capped by Australia and prop Johnstone had been capped by Zimbabwe, but both also had Scottish ancestry. At the tail end of 1999, the SRU were alarmed by a change in international regulations that meant a player capped by one country would no longer be able to play for another, so they arranged a game against Holland to tie the two players in.

So it was that Murdoch and Johnstone became eligible to play for Scotland. The irony of it all, however, was that neither was selected again.

In the light of such shenanigans, the SRU began to take more care with players. Indeed, they even went to the extent of seeking clarification from the International Rugby Board on the eligibility of two players: Paul Thompson and Simon Cross.

Thompson, the Borders prop, had sat once on the bench for New Zealand A, but hadn't been called into action. However, the IRB ruled that his involvement had tied him to New Zealand.

Cross had better luck with the game's global governing body. The flanker came from a military background, and a series of ancestors had drawn their first breaths in military hospitals. In strict terms, he had no direct Scottish eligibility, but the IRB ruled that he had a credible claim to be considered Scottish, and duly ruled in his favour. Sadly, he was never to win the cap he coveted.

The likelihood now is that the IRB will be called into action again to determine whether Shingler can play for Scotland or whether he is tied for all time to Wales. And the question must be why that issue was not settled before he was unveiled at Murrayfield yesterday morning.