Tax rule generally has nothing to do with nationality (although it is an important indicator towards your domicile status) - As you may be aware there are legal concepts such as resident, ordinarily resident and domicile. This area is currently being reviewed and will be replaced by the “statutory residency test” in the near future.
Under the current legislation, if you spend more than 183 days in the UK in the tax year you are deemed to be resident in the UK for tax purposes. This means your worldwide income and capital gains would be subject to UK tax.
Double tax relief is however available if you suffer local tax on the property disposal, up to the amount of local tax paid. For example, if you paid Chn tax at 10% on the gain, you will be subject to a further 8% or 18% of UK capital gains tax depending on your overall level of income. If the Chn tax suffered is more than the corresponding UK tax liability, no UK tax would be payable on the gain.
Under the self assessment regime the taxpayer is responsible for his own tax affairs and failure to comply would ultimately result in criminal prosecution. Of course in practice this is down to your own “appetite to risk”.
