Environmental group Greenpeace has annoyed some of its supporters in the Netherlands by writing to say their ‘donations’ are being increased, in some cases by as much as 100%.

Supporters who don’t agree with the extra donation have phoned Greenpeace to reverse the situation.

The letter has been sent to over 10,000 supporters in the Netherlands as a trial to test the response, the organisation said. In Scandinavia and Argentina, the same approach has considerably increased funding and just 5% of members refused to pay the new amount.

The organisation has taken on extra telephonists to deal with enquiries and complaints, Nos said.