Its quite simple really, we have an ageing population, the older the population gets the greater the death rate. The baby boomers that have been the engine of growth in the UK are approaching end of life. Demographics indicate that the death rate will continue to rise and peak over the next twenty years. Unfortunately because of this demographic timebomb the economy will suffer, pensions will become depleted and house prices will fall. The government have been trying to offset the coming financial catastrophe by importing people from other countries.
We could try to ignore reality and delude ourselves with conspiracy theories, but our greatest enemy is time and we only have three score years and ten.