For anyone thinking of handing their house to their child and paying them rent to continue to live there, and I appreciate that the OP does not intend to this, think very carefully before you do it.
As GSM has said, the rent you pay has to be the market rent for the property you live in. Market rents can rise - there has been a surge in rents in the last 2 years and if you live much longer than you expected, the rent can soon start to consume a very large proportion of your income.
I was once sent to advise someone in this situation, who had made an arrangement like this in his late 70s, assuming, he would probably die in his mid 80s. When I visited him he was in his mid 90s and going strong.
Because the rental market in his area and for his type of property had boomed, the market rent he was now required to pay was more than his total monthly pension, adding up both state and private pensions. What is more, HMRC checked the rent each year and his accountant had to show that the rent being charged was the market rent and was being paid.