Starting work without a contract?

[Not So Wise]

In regards to the one sided nature of the contract, welcome to contracting ...but As others have said, for a 4 week contract you don't need to stress to much about it as you are not really going to fall foul of IR35 (your main worry after payment) on such a short term contract, just make sure the terms about payment are to your satisfaction rest (as long as standard agency to contractor stuff) is pretty much imaterial

[TheFaQQer]

If it's only 4 weeks, I'dbe more concerned about any other restrictive clauses (e.g. going direct or through a different agency) than anything IR35 specific.

That said, regardless of contract length, I would never start work without agreeing the contract in writing.