IWAN Thomas faces his moment of truth at 9.04 at Crystal Palace on Sunday evening.

The British Grand Prix is his last chance to pin down a 400 metres individual berth at next month's IAAF World Championships in Canada.

Although the Southampton one-lapper did half the job by finishing second in the Trials at Birmingham last weekend, he is still short of the 45.72-second qualifying standard for Edmonton.

With a Monday deadline looming and no European races available, the Netley-based European and Commonwealth champion lodged a late entry for Wednesday's Bedford International Games but promptly withdrew again because of the poor conditions.

"I was up in the area in any case visiting my mum and dad and would have run if the conditions had been right," he explained. "But it was so cold, windy and wet that there is no way I was going to run fast."

Unless Britain's temperamental summer weather improves dramatically in the next couple of days, it won't be a balmy night at Crystal Palace either, but Thomas insisted: "I'm not bothered about the race being so late. I've just got to go there and do the job required."

Whatever the temperature in south London, the field is guaranteed to be red hot.

Jamaica's Olympic bronze medallist Greg Haughton heads a star-studded line-up which also includes American Jerome Young and the Saudi Arabian world junior champion Hamdan Al-Bishi.

Of the five-strong British contingent, world indoor champion Daniel Caines - the fastest man in the country this year - needs to prove his fitness after pulling out of the Trials with a bruised fibula.

Mark Richardson, the only British one-lapper so far selected, is also running along with Mark Hylton and Thomas's fellow Welshman Jamie Baulch, who finished third and fourth at the Trials.

Thomas is already guaranteed a trip to Edmonton in the 4x400m relay but he will be a bitterly disappointed man if he is not among the individual names when the British team is finalised on Monday.