With effect from 6th April 2015, non-resident individuals who dispose of UK residential property will potentially be liable to capital gains tax on any gain realised between 6th April 2015 (or later if acquired after this date) and the date of disposal.
This is unlike the disposal of other chargeable assets which are exempt provided 5 complete tax years of non-residence is achieved.
Temporary non-residents, i.e. those who do not achieve 5 years of non-residence, are assessed for capital gains tax on all gains realised from the date of becoming non-resident, in the tax year of returning to the UK and becoming UK resident.
It is recommended that a written valuation is obtained from an estate agent or valuer of the market value of UK residential property owned at 6th April 2015 as evidence of the base cost for any subsequent disposal. Alternatively, the capital gains tax calculation can be made on a "straight line" basis by using the original acquisition cost and time apportioning the gain from 6th April 2015 to the date of disposal.
The legal/sale costs (and possibly the purchase and any capital improvements costs) can be deducted to reduce the chargeable gain.
In addition to the annual exemption (available to EEA citizens and individuals who are a national or resident of a country with whom there is a double taxation agreement with the UK which grants personal allowances) there are other reliefs that may be available.