A PHONE call from Peter McColgan to his brother, Aidan, at the roadside during yesterday's London Marathon, was instrumental in launching Catherina McKiernan to a breathtaking victory over his own wife, Liz.

Watching on TV at race headquarters, Peter heard commentary to the effect that the main group, which included his wife, was falling behind the two leaders.

''I phoned Aidan, and he yelled to Liz, telling her she was 90 seconds down, and it was time to get a move on,'' said Peter. Unfortunately, it provided a wake-up call for McKiernan, running shoulder to shoulder with the Scot, who also heard the message and responded to devastating effect.

From the 16-mile mark, she broke clear alone, cut down Lydia Simon and Adrana Fernandez, and went on to win despite a spirited counter-attack by McColgan, who proved the faster over the final miles, but it was too late.

The Irish girl's coach, Joe Doonan, said: ''I believe, and Catherina believes, that she can now break the world best.''

Marathon running is rarely a glamourous pastime. Ask those in the record number of more than 29,900 who finished yesterday, braving gusting winds and, for all but the best, squally rain. Particularly, ask McKiernan, who found even victory hard to stomach - trying to avoid TV cameras for almost half of the race, after a gastric upset that left her laughing off embarrassment.

She finished in 2hr 26min 26sec, remarkably overcoming recurrent diarrhoea to beat McColgan by 29 seconds after a cat-and-mouse battle, with last year's winner, Kenyan Joyce Chepchumba, third. As the big guns eyed one another warily, at modest pace, the foot-soldiers threatened to steal a march.

The Irish woman showed herself to be Europe's leading marathon runner, winning her second outing at the distance, after having recorded the fastest debut in Berlin last year.

Yet McColgan was only two seconds slower than her own best time when losing by a single second 12 months ago.

A farmer's daughter from County Cavan, McKiernan may reflect that where there's muck, there is money. She collected $65,000 in winnings and bonuses, and ensured her future appearance fees are top of the league.

''My legs were all right, but my stomach was grumbling away. I have never experienced anything so embarrassing in my life, and don't want to again,'' she said. ''I had it under control for a while, but nature called, and I could do nothing about it.''

Doonan, who prepares her with scientific precision, using data from treadmill tests at Trinity College, was initially mystified by his protege's failure to follow the blue line denoting the shortest route. ''Then I realised why - she was trying to avoid the cameras. She didn't make a pit stop - just kept on going. It's a measure of the kid that she lived through that, stayed focused, and still won.''

Approaching 22 miles, McColgan was a minute down on McKiernan, but at 23 she had closed to 47 seconds, and narrowed to 29 at the end. The Scot said: ''Looking back, I should have gone earlier, but sometimes you make mistakes. Two seconds short of my best in adverse conditions convinces me my best marathon is still to come. I am certainly not giving up.

''Catherina is one of the best marathon runners in the world and I can't be too disappointed.''

Her $45,000 in winnings and bonuses will help assuage the pain.

The race was bad news overall for Scotland's Commonwealth Games hopes - no man or woman came anywhere near the respective qualifying times - McColgan has declined to run for well-publicised reasons involving her former coach, who is team manager. Indeed, City of Glasgow's Sandra Branney, at 43, is the next best Scot to McColgan.

Snatching the headlines as the oldest female finisher was another Dundee women, former councillor Jenny Wood-Allen, who finished last night in 7hr 21min 32secs, at the age of 86.

Chris Moon, the landmine victim running for the Diana Princess of Wales Memorial Fund, finished in 4-36, quickest of his 16 marathons since losing an arm and a leg in 1995.

Heinz Frei, world wheelchair record holder, was undaunted by having won in Hamburg just last weekend. The 40-year old Swiss, who pushes the wheels 80 times per minute, took four minutes off the course record, while Tanni Grey won the women's race for the fourth time. Details:

Women: 1. C McKiernan (Ireland) 2-26-26; 2. L McColgan (Scotland) 2-26-54; 3. J Chepchumba (Kenya) 27-22; 4. M Renders (Belgium) 2-27-30; 5. L Simon (Romania) 2-28-41; 10. M Sutton (England) 2-32-14; 24. S Branney (City of Glasgow) 2-48-47; 45. M Creeber (Edinburgh Woollen Mill) 3-00-54. Leader's split times. 5 miles: 27-10; 10: 55-02; half: 1-12-28; 15: 1-22-54; 20: 1-51-52; 25: 2-19-48. Wheelchair: T Grey (England) 2-02.1

Men. 1. A Anton (Spain) 2hr 07min 57sec; 2. A el Mouaziz (Morocco) 2-08-07; 3. A Pinto (Portugal) 2-08-13; 4. J Rey (Spain) 2-08-33; 5. A Mekonen (Ethiopia) 2-09-52; 6. R Stefko (Slovakia) 2-09-53; 7. D Garcia (Spain) 2-10-35; 8. J Brown (England) 2-11-10; 9. S Moneghetti (Australia) 2-11-40; 10. K Jitsui (Japan) 2-12-46; 16. M Hudspith (England) 2-14-19; 21. W Burns 2-16-11; 24. S Brace (Wales) 2-16-34. Leader's split times. 5 miles: 23-56; 10: 48-25; half: 1-04-01; 15: 1-13-05; 20: 1-38-11; 25: 2-02-04. Wheelchair: 1, H Frei (Switzerland) 1-35-18 (record); 28, G Shearer 2-40-23; 30, G Wemyss (first quadraplegic, both Red Star) 2-47.50.