The scheduled reopening of Wembley Stadium in May is looking increasingly unlikely after the firm installing the life safety systems has walked out in a dispute over pay.

A R Security has been putting in fire alarms and a voice alarm system to guide the 90 000 spectators out during an emergency. The company ordered its employees to stop work on 23 January in a dispute over money.

The stadium is due to be completed by 31 March, with two full-scale test events scheduled to take place before the Cup Final on 13 May.