LONDON is the venue this evening for Sonia O'Sullivan's last public examination before taking her hopes and those of millions of her supporters to Atlanta later this month.

This evening she faces the challenge of confirming her superiority over Catherina McKiernan, in what is the only meeting between the First Ladies of Irish athletics in two years.

And if the evidence of the 5,000 metres race, is merely peripheral in the context of establishing the plot for the Olympic Games, it still promises to be a riveting occasion.

Even by her own high standards, it has been an exceptionally rewarding month, so far, for O'Sullivan. From a situation in which lingering doubts survived from her winter injury, it has all come right precisely on schedule.

First, there was that significant 1,500 metres win in Oslo last Friday when, forced to dig deep for the only time this season, she came up with a superb finishing run to scatter some potential threats in Atlanta.

Then, there was the deep reassurance of Wednesday's performance in Nice where, in modest company, she still contrived to run the fastest 3,000 metres of the season in eight minutes 35.42 seconds.

The quality of both runs was sufficiently good to induce raw apprehension among those who seek to deny her Olympic gold. And still, she covets the satisfaction of victory at Crystal Palace.

"Winning is a habit and after putting together eight in a row, I don't want to break it now," she said. "And while it's just another race on the Grand Prix circuit, it's a very important one from where I stand.

"There has always been healthy competition between Catherina and myself and I believe we both like it that way. She has different targets to mine in Atlanta, but I'm certain it's every bit as important to her to win at Crystal Palace, as it is for me.

"Both her 5,000 metres runs this season have been very good and now that she's just down from altitude training, she has every reason to believe that she's going to run a big race.

McKiernan desperate to disprove the theory that she is incapable of making the transition from cross country to track competition, carries little of the burden of expectancy which O'Sullivan must take to Georgia.

Yet, those of her rivals who dismiss her chances of success in the 10,000 metres, do so at their peril. For all her brittleness on big track occasions, she still retains, many of the components necessary for championship success and she will be keen to make the point as convincingly as she can this evening.

Zohra Quaziz of Morocco, a bronze medalist at the World Championships in Gothenburg, will also be on the start line, but, otherwise, there is not a lot of depth in a race which, hopefully, is going to condense into a rare Irish duel over the last 800 metres.

Shane Healy is among those listed to take on the hugely talented Venuste Niyongabo over 1,500 metres and Ireland will also have an input in the high jump in which Mark Mandy, another of those headed for Atlanta, will be in the august company of such as Charles Austen, Tim Forsyth and Patrik Sjoberg.

As ever, Linford Christie will be the big draw for home supporters. After choosing to sit out this meeting last year, he now returns in the hope of rediscovering some of his old power and rhythm in the countdown to the defence of his sprint title in Atlanta.

Jonathan Edwards, still Britain's safest bet by far for Olympic gold, will woo the crowds in the triple jump event and there should be a big welcome, too, for the returning Kenyan Moses Kiptanui in the 3,000 metres.

After withdrawing from scheduled engagements in Oslo and Nice in some controversy, Kiptanui has the chance to illustrate his claims to still more honours in a field which, in addition to the American Bob Kennedy includes his compatriots. Ismail Kirui and John Kosgei.

. Allen Johnson urged Colin Jackson yesterday to find his old form at the Olympics even though he knows it could cost him the gold medal in the 110 metres.

The 25 year old American succeeded the injured Jackson as world champion last year and has won their three meetings so far this summer. But he admits that the Welsh man has been a shadow of his former self.

"I just want him to get his form back. I enjoy the competition. With Colin going well, we could go under the world record," he said.

Johnson, who came within one hundredth of a second of Jackson's record with 12.92 in the US trials on Atlanta's ultra fast track, is looking for a fast time tomorrow to set him up for the Games.

Jackson is already in the United States, so Tony Jarrett provides the major domestic opposition.