Solar Panels Should Be Compulsory On New Buildings

Here in the UK there is widespread discussion on how to increase our use of renewable energy. One simple method, that I have never heard a government official mention, is to bring in legislation to install a solar panel on every new building.
I installed a panel some years ago and it provides hot water for 7 months of the year plus a little more on sunny days during the winter.
Apart from a small grant, I paid for the installation myself. The cost of installing on a new building should be negligible in the overall cost.
I would like to see the government provide 100% grants towards solar hot water for all existing homes, just as they did many years ago to provide bathrooms for old housing stock.
The solar energy industry claims the panels provide up to 70% of hot water needed.
[solar panels]
[solar energy]
[grants]
[solar hot water]