EU negotiators have agreed a deal to establish common European rules over what can be considered a green investment, although the exact nature of how nuclear energy projects will be affected has not been confirmed.

The categorisation system, or “taxonomy for sustainable activities”, decides which financial products can be marketed as green and was agreed by the European parliament and EU diplomats on Thursday following weeks of talks in Brussels.

The rule book, which will cover all types of energy sources including nuclear, will help investors decide how to treat a range of assets from green bonds to bank loans and investment products.