I'm afraid the law is an ass, something similar is happening to my mate's mum at the moment. She fought hard for the house at the end of her first marriage, and now her second husband (who never paid a bill in his life) is claiming for half of it!!!! Your partner needs to prove that he loaned her money and that she was making repayments. If you can't do that, you could always consider your partner selling you (or a close friend, but not family) the house for �10, in which case if she won she would only be entitled to half the value of the sale (�5). Of course to secure your partner's ownership after the case is over before any sale went through it would be worth drawing up a contract stating that the house will be sold back to the original owner at the same price. This is expensive in terms of legal costs, but does ensure she won't get anything. Of course this is only based on her being his wife / common law wife (a co-habitor). The less secure their relationship was, the less claim she has on his property and money. Unfortunately, she has nothing to lose in this situation (especially if she is getting legal aid) so chances are she will pursue this as viciously as she can, your only option is to fight dirty too.