The WWF format, which is simply a PDF that cannot be printed out, has been launched by the environmental group in a bid to "stop unnecessary printing and encourage a new awareness about the use of paper".

In a campaign that has been widely picked up by the media, the WWF has urged the public to "Save as WWF, Save a Tree". The move represents a major blow to the work Two Sides has been doing to try to clear up some of the misinformation about the sustainability of print on paper.

According to its website promoting the new file format, the WWF wants to "create a new awareness about the use of paper" and make it "easy for everyone to contribute to saving our forests".

Two Sides director Martyn Eustace said: "This WWF has made a ridiculous statement based on two false premises, firstly that the paper industry is destroying trees, and secondly that viewing documents on a computer is somehow better for the environment.

"Trees are a renewable resource and print on paper is definitely one of the most sustainable ways to communicate, obviously as long as it's done correctly. The WWF does a lot of good things but it is dangerous to suggest that electronic communication is somehow free of charge environmentally - it has an impact all of its own in the energy used to power these devices.

"We will robustly challenge the WWF on this because if we allow them to mislead the general public with this misguided message it has the potential to be very damaging to our industry."

The print industry will need to move quickly to respond to the WWF's claims and its implicit message that printing destroys trees, harms plant and animal habitats and removes "another layer of environmental protection".

BPIF director of corporate affairs Andy Brown said: "The WWF is quite clearly impying that the consumption of paper 'destroys trees' whereas, in actual fact, paper is a crop.

"This has absolutely got to be challenged."

WWF could not be reached for comment at the time of writing.