The office where I work is closing down and we are possibly relocating. I have worked there for 5 years and have never had an employment contract.
This was ok, I could live with it, but now my boss wants to draft one for us to sign to say we don't mind working anywhere the area if relocated and also that we would accept being laid off for a period of time while the relocation took place.
Is it ok for him to lay me off with no pay for a period?
Don't sign anything - you do have a contract now, even if you do not have a signed document. Your contract started the day you started work and your current conditions are your terms of employment. Speak to ACAS urgently. Employers can change your contract, but you have to agree. It is also law that you have a Contract and it appears they are in breach of that.