You need to make a substantial contribution to the actual fabric of the property. As ummm says, sharing in the bills is just living expenses. After all, you would have to pay to live somewhere.
Ummm, I've got a similar case at the moment to what you describe. Unfortunately HE is claiming that THEY agreed that if he paid £x per month he would gain a beneficial interest. She says "poppy cock" it was just his contribution to food and "rent". Unfortunately, it's going to cost her to fight him because its a factual dispute. This is a rapidly developing area of the law, despite the House of Lords thinking they had solved the problem!!
Carmalee, I can well believe it - however your case concerned a death so I suspect that what we were looking at here was a claim under the Inheritance Act (I could be wrong) as a cohabitee or dependant. That's quite different to claiming a beneficial interest in a property by virtue of contributions. However, I do agree with you and always advise - GET IT IN WRITING!!!