It can often be very difficult to interpret double tax treaties, not least because the terms and definitions they use don't necessarily overlap with those in the UK tax system.

The OECD website has a helpful glossary of tax terms which provides condensed definitions of a large number of terms used in the OECD model treaty.

As the majority of the UK's tax treaties are based on this model this can be a helpful starting point in trying to decipher them.