Wholly agree with Factor 30 here. In addition to what he says there are 'equity release schemes'. There are many providers and I will provide a link to what Prudential say on the matter - not because I am recommending it but because it seems to explain them clearly.
Basically the provide a cash sum to the home owner to exchange for either a loan secured against the property (a larger mortage essentially) or in exchange for part of the equity share of the house. The company gets its money back when the homeowner dies (so it comes out of the value of the estate of the deceased)
The first type are called 'lifetime mortgages', others are called home reversion schemes. With the latter, you lose part of the equity.
You must get proper financial advice before deciding. Talk to Age Concern first, who will not provide the advice but will know a man who does.
http://www.pru.co.uk/equity_release/guide/using_home_equity/