A double taxation agreement (DTA), also known as a tax treaty, is an agreement between two countries that aims to prevent individuals and businesses from being taxed twice on the same income or gains. DTAs are designed to promote cross-border trade and investment by reducing the tax barriers and uncertainties that can arise from differences in national tax laws.

Under a DTA, each country agrees to certain rules for taxing income and gains that arise from cross-border activities. For example, a DTA may specify which country has the primary right to tax certain types of income, such as dividends, interest, or royalties, and may set limits on the amount of tax that can be charged.

DTAs also provide for the exchange of information between tax authorities in different countries to help prevent tax evasion and ensure that taxpayers are paying the correct amount of tax. This can help to increase transparency and reduce the risk of double taxation, as well as provide a framework for resolving any disputes that may arise between tax authorities.

In the UK, the government has negotiated DTAs with over 130 countries, including many of the UK's major trading partners. The terms of each DTA can vary depending on the specific countries involved, so it's important for individuals and businesses to check the terms of any relevant DTA to understand their tax obligations and entitlements. It's also a good idea to seek advice from a tax professional who can help navigate the complexities of international tax law.