Workers have rejected a new pay offer

Scaffolders, labourers and others went on strike on Tuesday after a new offer to increase bonus pay by 80p an hour was rejected.

Workers at the �4bn west London site are demanding a �1-an-hour rise in bonuses and have already taken part in strikes in December and January.

Employers Laing O'Rourke had previously offered an extra 67p-an-hour.

Their latest offer had been recommended for acceptance by union shop stewards but was overwhelmingly rejected at a series of meetings.

Phil Davies, of the GMB union, said: "Laing O'Rourke have misjudged the mood of the workforce right from the start of this dispute."

Heathrow Airport said previous industrial action had not disrupted building at the terminal which is due to be completed in 2008.