JAMIE Baulch is out of the British men's 4x400m relay team, giving teenager Tim Benjamin the chance to make his championship debut.

Baulch's injury-hit season continues after the Risca sprinter failed to qualify from his 400m heat and he has struggled all season with a back injury.

Baulch's bad luck means 19-year-old Benjamin, Christian Malcolm's training partner, is expected to step up into the team alongside Iwan Thomas, Mark Richardson and Mark Hylton for Saturday's relay heats.

On the track, Britain's interest in the men's 1500m will continue into today's semi-final as John Mayock and Anthony Whiteman both qualified, despite some fast times from their rivals.

Mayock finished eighth in a strong field and said he had not expected to have had to run so fast, but his time of 3mins 39.24secs was enough to see him through, with El Guerrouj Hicham of Morocco winning in 3mins 36.97secs.

Although Mayock went through as a fastest loser, Whiteman ran a gutsy race to finish as the last of the six to qualify and ran a season's best 3mins 37.75secs.

Things are looking up for top American sprinter Marion Jones, who is favourite for the women's 200m gold.

Having lost Sunday's 100m final to Ukranian Zhanna Pintusevich-Block on Monday, the Olympic champion flew through her semi-final in a time of 22.40secs, with only Debbie Ferguson of the Bahamas running faster in a time of 22.39secs.

In the pole vault, Australian Dmitri Markov made the event his own after setting a new championship and Commonwealth record of 6.05metres.

With the crowd doing their best to get behind him, Markov went all out for 6.10 (the world record is 6.14m) but had to settle for two new records and a gold medal - not bad for a day's work.

In the men's 110m hurdles final, with no Colin Jackson to defend the title, American Allen Johnson took the title from Cuba's Anier Garcia by just three hundredths of a second. Johnson ran the fastest time this season, 13.04secs, despite hitting six of the ten hurdles.