Paula Radcliffe believes tomorrow's BUPA Great North Run will help her decide when she will move up to the marathon.

After finishing a gallant fourth in the Olympic 10,000 metres final in Sydney, the British team captain will race against world marathon record holder, Tegla Loroupe of Kenya, over the half-marathon distance.

''I think Sunday will provide an indication where my future really lies,'' said Radcliffe. ''But that doesn't mean if I run really fast I'll immediately do a marathon.

''I'm 26 now so I would definitely like to run a marathon before I'm 30. Let's see what I get out of the track in the next couple of years.

''But at the moment Sunday is important to me.''

Radcliffe was outsprinted over the final lap after leading for all but two circuits inside Stadium Australia.

She admitted: ''I was bitterly disappointed and really down about it.

''But if you ever let it get to you, you might as well retire or step away from the distance. What you have to do is put it behind you and get on with your career.

''At the end of the day I ran a personal best for the distance and also a Commonwealth record. I felt I ran it the best way possible and would have felt a lot worse if I'd just sat in and finished fourth.''

Radcliffe, who finished third in her debut over the half-marathon distance in last October's Great North Run, revealed: ''I think next year I will definitely stay around the five and 10km.

''There was always pressure for me to move up to the 10km but I didn't do that until I thought I was ready.''

Radcliffe thinks she can challenge the 12-year-old course record of 68 minutes 49 seconds held by the legendary Norwegian Grete Waitz.

After clocking an English record of 69 minutes 37 seconds a year ago, she added: ''People forget I'm still young because I've been racing in championships since I was 18 or 19.

''This race will only be my second half marathon.

''The last three miles were really painful last year but going into the race I wasn't in the right sort of shape.

''It came at the end of a long, hard track season. My body had had just about enough and it took a lot of effort to run it. This year through injury I started very late and will be better prepared.''

Radcliffe also believes she can approach Liz McColgan's British record of 67 minutes 11 seconds.

She said: ''Liz has always been a bit of a hero to me and over the years I have successfully sliced away at some of her records.

''I think it is possible to run a faster half marathon than she did but the course on Sunday is a tough one and I'll be more intent on winning than running for the time.

''A tactical race where we watch one another inevitably means the time is slower.''

While either Radcliffe or Loroupe is almost certain to become the 20th women's champion of the half marathon, who wins the men's 13.1-mile race from Newcastle to South Shields is wide open.

Having persuaded Karl Keska, who finished eighth in the Olympic 10,000m final, to make his debut at the distance, organisers have pitted the Midlander against the best field ever assembled for the annual Tyneside classic.

''The entry list is as good as any international marathon,'' said Mexico's Dionicio Ceron Ceron, who completed his hat-trick of London successes in 1996.

Keska will also square up to former world marathon record holder Ronaldo da Costa, reigning London champion Antonio Pinto, former world and European marathon winner Martin Fiz and world silver medallist Vincenzo Modica.

Another threat will be Tanzanian superkid Faustin Baha. The 18-year-old ran a phenomenal world junior record of 59 minutes 38 seconds in Lisbon in the spring.

Keska knows he is entering new territory, but said: ''Like most athletes I do plan to move up to the marathon distance eventually.

''The half marathon is a natural stepping stone. It's a great field that has been assembled and I'll be giving it my best shot.'