Company medical plans could be cut in the same way as final salary pension schemes have been slashed if treatment costs continue to rise at their current pace, says one of the biggest corporate advisers on healthcare schemes.

The average cost of providing medical cover for employees and dependants has risen by 67 per cent since 1999, according to a survey of more than 250 companies with a combined annual claims spend of £142m by Mercer, the business consultants.