The group, which is the first quality newspaper to make such a move, claimed the decision had been made to "to increase transparency in the newspaper industry".

Traditionally, bulk copies have been used in the industry to boost ABC figures for advertisers and as a way of sampling to new readers in locations such as hotels and airlines.

Last month's ABC figures were the first officially ratified figures to include bulk distribution, a move supported by most newspapers.

However, Joe Clark, GNM director and general manager for newspapers, said: "To a greater or lesser degree bulk sales are used by newspaper groups to prop up their ABC figure. 

"Yet their credibility in the ad community is low and for those affected by the recent investigation into airline bulks that credibility has been undermined further. 

"We are abandoning this practice in order to present a clearer, more honest picture of our sales performance to advertisers and to reinforce the quality of our product to readers.

"The success of our subscription scheme has proved the value of rewarding loyal readers and prompted us to question the merit of subsidising a free copy for an occasional reader."

Dropping the bulk distributions will cut 12,000 newspapers from the The Guardian's figures and 20,000 from the The Observer – 3.9% and 5% of the totals respectively.

Compared to other newspaper groups, bulk sales constitutes a fairly small proportion of The Guardian and The Observer’s overall sales figure.

Clark added: "In short, dropping this traditional and, in our view, out-moded practice is a win-win move. We hope that others will follow our lead."