AT the Woodside Stadium, Watford, today a number of leading Scottish male athletes will sail into action for the first time this season hoping to fire the first salvoes in their bid for selection for the Commonwealth Games in Kuala Lumpur in September.

The occasion is the opening round of the British League first division and several of the Scots will be wearing ''flags of convenience'', the colours of English clubs, as they seek to take advantage of the top competition on offer.

It is a situation which has existed for many years but is given added piquancy this year; for, making their team debuts in the top flight will be last season's second division champions Border Harriers, who are based in Carlisle and have rocketed up through the league with the help of several Scottish athletes, and the City of Edinburgh AC, the only Scottish-based club in the entire British men's league. What is particularly galling for

officials of both clubs is that staying in the top

division may prove a much harder task than reaching it. The euphoria which surrounded last season's final second division match at Dumfries, when the City combine eagerly looked forward to welcoming back their prodigals into the fold, has been replaced by cold realism and not a little disillusion as the athletes have stayed put.

As Neil Donnachie, the Edinburgh team

co-ordinator, put it earlier this week after his fourth top athlete had called off: ''It makes you wonder if it's all really worthwhile and I'll certainly be suggesting a review of what we do for next year.''

Why, for example, have Douglas Walker and Ken Campbell, both former members of Edinburgh clubs, failed to return to the fold? The reasons are complicated but basically to do with the rules on first and second claim clubs.

Walker won the East District 100 metres titles in the vest of Newham and Essex Beagles last Saturday despite the fact he was running in his native Edinburgh and is a secondary first claim member of the City of Edinburgh club. Today, if he has recovered from an injury, Walker will line up again in the 100 metres against his City club-mate and training partner Elliot Bunney.

That may be good for them as, had they been in the same team they would have had to choose between the A or B race. But the British League would have provided ideal practice for the Scottish relay squad they both aspire to and which will have precious few chances to prove its case for selection for Kuala Lumpur.

It is difficult to justify blaming individuals. New friendships have been formed and loyalties forged. Perhaps no-one has offered to make sure such athletes would not suffer financially by donning Scottish colours again. Certainly they did not suffer by migrating in summer as the English clubs would at least cover their expenses.

After many years of flying the flag for Scotland in the league, the capital clubs' fortunes slumped. Edinburgh Southern, British cup champions in 1975, slid to division three and rivals Edinburgh AC dropped even further, the strain of finding athletes to cover all the events proving too great. Walker, who initially stayed loyal to the latter, was one of many who advocated a merger but when it came it was too late: he had moved on in search of better competition.

It has always seemed extraordinary to me that athletes from other parts of Scotland, and in particular the West, would opt for an English club when a Scottish one was available. Is the problem, perhaps, the old one of the only good thing coming out of Edinburgh being the road to Glasgow? This attitude at one time appeared to run so deep that West officials who then dominated the Scottish AAA seemed positively anti-league; and in one episode scheduled a Scottish international against Iceland on the same day as a British League match thus putting the Scottish internationalists in the Edinburgh Southern team in an club v country conflict. That was the season before the 1978 Commonwealth Games and a gun was put at the athletes' heads, yet some who opted for country never made the Games team while Southern lost the match and with it the only real chance a Scottish team has had, before or since,

of winning the prestigious first division title. Perhaps Edinburgh and the Scottish Athletics Federation could co-operate to enter as Team Scotland and apply for Lottery money from the top performers budget.

Fixture clashes still occur - tomorrow the second round of the Scottish League is due to take place at Grangemouth with the City of Edinburgh expected to turn out a team to protect their lead from the first match despite today's Watford commitment. Next month a British junior international in Spain takes place on the same day as the Scottish Championships, the official selection meeting for Kuala Lumpur, with a major meeting at Gateshead the next day. What a dilemma for the athlete with a conscience, for whatever he or she chooses the sport will be the loser.