To put it further into context £240 billion is slightly less than what the UK government spends on pensions and welfare. Since basic income would replace much of the need for pensions and welfare, it might just end up more or less balancing out.
Note that this £240 billion will have the overheads of running the welfare system built into it too. So the actual pension checks are only a percentage of that figure, with a basic income that's not means tested the government has far less overhead.
