Working Week 36. Mr. van Straubenzee asked the Secretary of State for Employment what he estimates would be the cost to the British economy of a reduction in the standard working week to 39 hours. Mr. Jim Lester My Department has estimated that a reduction in the standard working week to 39 hours could add up to 2ยท8 per cent. to the national wage bill. This estimate takes no account of the longer term effects of such a reduction, which could undermine the productive capacity and competitiveness of British industry.