Negotiators were very happy when the European Parliament and the EU's Council of Ministers agreed over a new directive to define what counts as a green investment in the EU.

However, this happiness was short-lived, as just one week later, it is clear that the negotiators will have to go back to the drawing board. It is normally a formality to gain approval from the EU council of ministers once a compromise has been reached, but not this time.

At a meeting of EU ambassadors, a minority blocked the deal, according to information obtained by FinansWatch.

Apparently, France, the UK and several Eastern European counties opposed the fact that nuclear power was not explicitly defined as a climate-friendly technology.

To get the deal passed, the negotiators had planned for a group of experts to decide how far nuclear power could be considered to be a green investment.

However, according to Euractiv, it would probably not have been considered green by the experts, as they would not only consider CO2 emissions, but work from a principle that the technology should not do harm.

As the EU's Council of Ministers cannot agree, the negotiators must try and find a new deal - but as it is unclear whether the European Parliament would accept the inclusion of nuclear power, the future of the directive (which has so far taken 18 months to negotiate) looks uncertain.

English Edit: Catherine Brett