I picked up on this point on the BBC News 24 this morning.

If your employer, as part of a package, to keep people in work, instigates a pay cut for staff. Should your employer then go on to make you redundant. For the purposes of Statutory Redundancy the rate used in the calculation will be your final salary. Clearly if you have taken a pay cut your basic entitlement will also be "cut" to reflect this.

If your employer wishes to reduce your wage because of the 'economic downturn'. It may well be worthwhile to ask that should the company go on to make redundancies. They will do so at your pre-cut salary rate. If your employer agrees, as this will be part of your Employment Contract. Get something in writing confirming this agreement.