Even if there's nothing in writing, a contract exists between you and your employer. (If I agree to your offer to do your shopping for a fiver we've both entered into a legal contract. There's no need for a written document).
If someone owes you money, and you don't get it, all that you can do (which doesn't involve a couple of big guys with baseball bats) is to follow this procedure:
1. Issue a formal, written demand for the money which is due to you. Your letter must show your own name and address and the name and address of the person (or firm) who owes you the money. (If it's a limited company, the letter should be addressed 'to the Company Secretary'). The letter must also be dated. It should state that it is a formal demand for payment, quoting the amount due and why it is owed to you. The letter should clearly indicate that if payment is not received within a specified period of time (I suggest 14 days) you will commence legal proceedings. Keepa copy of the letter and send the original by recorded delivery. (Retain the proof of posting).
If you don't get your money . . .
2. Commence court action, using the online procedure here:
https://www.moneyclaim.gov.uk/web/mcol/welcome
Once you've got your court judgement, if you still don't get your money . . .
3. Commence enforcement action:
http://www.hmcourts-s...enforcement/index.htm
Chris