Chambers, who served a two-year ban after testing positive for the steroid THG in 2003, secured his place at Valencia by winning last weekend's 60m trial in Sheffield.

The 29-year-old's participation has been widely condemned and Coe, a double Olympic middle-distance champion, is concerned by the damage done to the sport by the recent spate of doping scandals.

Coe claimed athletics cannot survive further high-profile cases such as Chambers' and maintained there is no hiding place for drugs cheats.

"Am I uncomfortable at Dwain being picked? Of course I am. My sport is incredibly fragile at the moment," he said. "If the previous five years were to happen again, where would we be?

"What happened in the last five years is not sustainable on a consistent basis. These days there are no unhappy circumstances where athletes don't know what they're doing.

"This is not 30 years ago when a 14-year-old child behind the Iron Curtain was given something at breakfast and told that it was part and parcel of becoming an international athlete.

"With the amount of money being spent on education programmes I do not accept there are any circumstances where athletes like Chambers can get sucked into something without being complicit."

Coe felt UK Athletics were compelled to include Chambers in the British team but is scathing of the selection criteria that has enabled him to compete in Spain.

The UKA selection committee were "unanimous in their desire not to select him" but with Chambers having won the trial, were powerless to omit him.

"UK Athletics had no alternative," said Coe at a book launch for 'Running the Race', a biography of Olympic champion Eric Liddell. "We know that to have left him out would have been legally challenged under their own selection process, which is first past the post.

"I'm ambivalent about a selection policy that gives first past the post unfettered access to the championship.

"Selection should be left to selectors and should be intuitive, picking on past form, current form, conduct in the sport and potential.

"Once you've got the first past the post system in place you have people who are not fit to be in the team – ie they just got lucky on the day – or, frankly, people you would rather not pick. All of the selectors were clear that they'd rather not have picked Dwain."

Coe will continue his campaign for the minimum two-year ban for athletes testing positive for steroids or other serious banned substances to be extended to four.

The International Association of Athletics Federations reduced the penalty in 1997 after courts in several countries refused to uphold the longer ban.

"Since I started with some like-minded people in Helsinki in 2005 to move the ban to four years, we've had partial movement," added Coe.

"I still think that eventually we'll get to four years and that's really important. But so long as our chief response is only two years out of the sport, we're lumbered with the rules."

GB & N Ireland team, first wave, men – 60m: D Chambers (Belgrave); 400m: R Buck (City of York), S Green (Newham & Essex); 800m: R (Notts AC); 1500m: J McIlroy (WSE Hounslow); 60m hurdles: A Scott (Shaftesbury Barnet); high jump: S Oni (Belgrave); pole vault: S Lewis (Newham & Essex); long jump: C Tomlinson (Newham & Essex); triple jump: P Idowu (Belgrave); shot put: C Myerscough (Blackpool); 4x400m relay: Buck, Green. Women – 60m: L Turner (Harrow AC), Je Kwakye (Woodford Green & Essex); 800m: J Meadows (Wigan), M Okoro (Shaftesbury Barnet); 1500m: J Simpson (Newquay & Par), S Scott (City of Glasgow); 3000m: H Clitheroe (Preston); 60m hurdles: S Claxton (Woodford Green & Essex); pole vault: K Dennison (Sale); pentathlon: K Sotherton (Birchfield).