The turmoil in the credit markets has sharply cut the value of interest rate and inflation hedges Mitchells & Butlers took out when it was planning a £4.5bn property joint venture.

The pub and restaurant group, which owns the All Bar One and Harvester brands, said on Monday that in marking-to-market the swaps it had put in place, the post-tax deficit had risen from £60m at the end of July to £140m by September 13.