Our expense policy states that any expense claims should be submitted by a deadline each month, which is set out for the year in advance within the central company calendar (accessible to everyone).  Expense claims are then paid a month in arrears.

We have also stated that any expense claims not submitted by these deadlines are not paid as we do not want staff accumulating several months expenses and then having to pay large amounts in one go – we also need to be able to cost against work and this is not possible if staff submit expenses every few months or as they feel fit.

Is this a fair or permitted policy, or do employees have a legal right to a refund on expenses irrelevant of when they are submitted or how old they are?