Jo Jackson's hopes of a higher placing were stifled after two warnings during the 20 kilometres walk final at the World Athletics Championships this morning.

Redcar's Jackson completed the course to finish 25th in a time of one hour 39minutes 34seconds, a good display in the tough weather conditions.

Olga Kaniskina, last summer's European silver medallist, was a runaway winner in 1hr 39min 9sec.

The 22-year-old Russian finished 33 seconds clear of team-mate Tatyana Shemyakina, this year's European Under-23 champion.

Spain's Olympic bronze medallist Maria Vasco tried desperately to overtake her 19-year-old rival, but had to settle for third position in 1hr 30min 47sec.

Jackson, the first Briton to compete in a walking competition since Lisa Langford finished 35th in the 10km track discipline 12 years ago in Gothenburg, was never expected to attain a top-10 finish.

But the 22-year-old British champion was hoping to secure a fairly high position in her bid to convince the selectors she is worthy material for next year's Olympic Games.

"I got to two calls before 10km, which stopped me going faster," said Jackson. "That meant I had to be careful to ensure I just finished.

"The cards were probably because of a little lack of concentration and fatigue.

"Coming here was never in my plans for the season, but I have learned a lot being here - especially about preparation - which will be useful for next year."

Ireland's Olive Loughnane found herself in the same position after being yellow carded in the first half of the race where the weather, although very hot, varied with showers and sunshine.

"I got two calls early on. That was frustrating because my plan was to start slowly and then push on hard . I couldn't risk that," said Loughnane, 17th in 1hr 36min 00sec.