Builders' threat to Opera House

Leaders of 40,000 construction workers yesterday threatened indefinite strikes at prestige projects including the Tate Gallery, Royal Opera House and the Millennium Dome in a dispute over pay.

The target sites, which also include the Newbury Bypass and the Channel Tunnel Rail-Link, could be hit by stoppages from 5 August, and plans drawn up by the Transport and General Workers Union and the GMB general union.

The Construction Confederation, the employers' group, is seeking a long term agreement on pay of up to four years, although unions are now attempting to thrash out a deal for this year.