There's a presumption in law that friends and family do not intend to create legal relations when they enter into these kind of "arrangements". This presumption can be rebutted (the onus being on you to rebut) if you have evidence to the contrary such as a written agreement (it doesn't have to be a formal document, just a handwritten letter setting out the agreement will suffice). Furthermore, for an agreement to be a legally binding contract, you must be able to demonstrate certainty of terms eg, that you agreed between you how the loan would be repaid. From my experience, I have to say that I think you have little chance of success based on the facts you have stated. However, as the Court fee is only �75 and you potentially (though remotely in my view) stand to gain �800, you might think it worth the gamble. You should write what is known as a "letter before action" to your proposed defendant before you issue court proceedings. The letter must set out in detail the facts upon which you are relying and the basis of your claim (ie, you would be claiming breach of contract, if you can indeed prove you have a contract) and stating clearly that if you do not receive proposals for settlement of the debt within 14 days that you will issue a claim in the small claims track at [name of town/city] County Court.