Denis Tunnicliffe, the chief executive, admitted that the completion of the line had been jeopardised by an electricians' strike and "poor productivity" of the workforce. He was speaking amid warnings that outside staff could be brought in to break the strike, as industrial action went into its fourth day.
"Unless productivity improves we will not be able to finish the line in time. The present situation is very serious and sad," Mr Tunnicliffe said.
He told the BBC Radio 4 Today programme that he was "totally confident" the extension of the tube line from central London to the dome in Greenwich, south-east London, would be finished, but only if the strike ended soon and if the workforce achieved "reasonable levels of productivity".
But there seems to be little hope of the strike being called off. Representatives of the electricians said there was no question of the men going back to work until management addressed the health and safety issue at the heart of the dispute.
Tony Miller, a shop steward with the Amalgamated Engineering and Electrical Union and one of the leaders of the unofficial stoppage, said the men walked out because colleagues had been victimised.
Among 12 workers transferred from the London Bridge site to Green Park were employees who had been vocal about safety deficiencies. He said that the company had been offered a range of peace proposals to end the strike, but had rejected them.
An official spokesman for the union, which has repudiated the unofficial action, said management threats to bring in alternative labour to break the strike were "not helpful". The union would continue to work within established procedures to bring an end to the disruption.
Earlier this year the final opening date of the line was put back to late autumn 1999, weeks before the dome opens. The line will now open in stages.
Meanwhile, Chris Raven, project director at Drake & Scull, was at pains to separate the dispute from allegations of vandalism. It was untrue to say the company had blamed electricians for causing pounds 100,000 worth of damage to cables.Reuse content