London requires new flats to have a CHP system, in practice usually gas-fired.
There’s a separate district heating and cooling discussion group I belong to, not part of the AECB. But if you’re outside London, as I am, this may be of limited applicability to you as there may be little support for the idea.
However, a central system of some kind would seem to be convertible to anything later, i.e. any source of heat. Electric systems, one per flat, certainly aren’t and there’s some concern about the peak in electricity demand in future winters like 2009-10, 2010-11. Gas and hot water can easily be stored, electricity can’t.