"If you are a pensioner and you want a free swim in London, choose a pool in Brent, Islington, Lambeth, Lewisham and Westminster and it won't cost a penny. If you are over 60 and still can't swim and want to learn, instruction is also free in Westminster and Lambeth. But avoid going to Bromley - where it is £3 a time and £10.20 an hour for swimming instruction or Richmond on Thames where it is £3.50 a session.
Outside the capital pensioners can only swim free in the Wirral and Wigan in England but have a much better choice in Wales. Here pensioners are not charged in Blaenau Gwent, Conwy, Ynys Mon (Anglesey), Powys, Rhondda, and Torfaen. ..."
So the answer seems to be keep fit and enjoying swimming in Westminster but move to Nottinghamshire when you think you are about to die. Figures are all supplied by the Chartered Institute of Public Acountancy.