The Two Sides campaign, which promotes the responsible production and use of print and paper, said it was concerned about the link made by the council between "reducing the use of paper and helping the environment".

Director Martyn Eustace said such suggestions created a false impression about the sustainability of print and paper.

In the letter, he said: "The belief that e-communication is more environmentally friendly than print is generally unproved and there is a clear lack of life-cycle data to support such claims."

He added it was increasingly clear that electronic communication, in particular the energy requirements of the worldwide network of servers that support it, had "a significant and increasing carbon footprint".

Eustace asked Cambridge City Council to reconsider its message that using an iPad is more environmentally-friendly than traditional paper.

Cambridge City Council has since denied that the Apple iPad was being considered.

However, it said one option it would address was "the use of notebook and tablet devices as a way to reduce paper, printing and waste disposal costs associated with committee reports".

The letter comes just days after Two Sides announced it would "actively challenge greenwash" that damaged print and paper's reputations.