If you have more than one home, – properties actually used as your home – you can elect for one of those properties to be your tax-exempt main home. Once this election is made, it can be changed at any time, and this allows you to manage the tax you pay when disposing of your properties.
However, from April 2015 the ability to elect for one property or another to be tax-exempt may well be removed. This is because the Government wants to tax overseas residents on the profits they make when they sell their homes in the UK.
Such overseas residents live in their UK homes for only a small part of the tax year, but currently pay no UK tax when those properties are sold (although they may pay tax in another country on the gain). If the election to opt for one property to be tax-exempt remained in place, all overseas residents would opt to have their UK home treated as their tax-exempt main home, and no additional tax would be raised.
So from April 2015 which property is your tax-exempt main home will be determined by factors such as where you are located most of the tax year, or where your family is based, or where the children go to school etc. It’s not clear how the elections which are currently in place will be treated.