confused - law

This is a perfectly common contract, OP. Yes, it's enforceable and in refusing to give you the money back the person would in fact be in breach.

There is no consideration moving from the promisee though?

Could I just ask, I am not currently studying law but will, hopefully, be next year, and I am just interested as to the answer. How would you be able to prove that the person said they would return the loan? Or the fact that it is even a loan at all?

That's a good question and the answer isn't really definite. It always depends upon the circumstances and facts of any individual case. It's generally good practice to carry out these sort of negotiations in writing where the proof of a signature provides "absolute" agreement to the terms within a contract. Indeed, if the OP were a business lending to another business and the contract was absent, the OP may in fact be denied (equitable) relief on that basis alone.

Generally, however, the courts will always assume that where money is given to one person it's usually "in consideration" for something else. An altruistic relationship (where one party gives a gift to another) is only ever likely to be assumed to have occured within a familial context and even then, only as between certain members.

it's the promise to give it back

Surely consideration has to have some economic or personal value - to be sufficient

any authority btw?

Obiter dictum, Foakes v Beer.

the original contract had consideration though (the interest)

Lending £1000 to a mate is the kind of situation where the courts probably are not going to intervene. Its very difficult to argue that there is intent to create legal relations in that kind of context.

If the £1000 was lent in a commercial context, I *think* it would need to comply with the Consumer Credit Act to be enforceable - this means that there must be a signed agreement giving various details, among other things. There may be a relevant exclusion but I don't think there is.

In any event, lending £1000 to be paid back on indeterminate terms by an indeterminate date is probably going to fail as a contract because it lacks certainty.

In short: it probably is not enforceable.

Lending £1000 to a mate is the kind of situation where the courts probably are not going to intervene. Its very difficult to argue that there is intent to create legal relations in that kind of context.

If the £1000 was lent in a commercial context, I *think* it would need to comply with the Consumer Credit Act to be enforceable - this means that there must be a signed agreement giving various details, among other things. There may be a relevant exclusion but I don't think there is.

In any event, lending £1000 to be paid back on indeterminate terms by an indeterminate date is probably going to fail as a contract because it lacks certainty.

In short: it probably is not enforceable.