Despite only becoming a free title in late 2009, the publication is now being sold, only five months later, in a selection of newsagents across north west London.

The Evening Standard, which prior to going free was a paid-for paper for more than 180 years, did not wish to comment on the trial, but it has been reported that prices are varying from place to place, with 20p and 50p the most common sale prices.

It is a similar trial to that of the Manchester Evening News, which was given away free in the centre of the city last year, but sold on the outskirts.

This was believed to be a way of reaching young professionals, while also recording a cover price – a balance that freesheet newspapers have found hard to achieve.

Russian media mogul Alexander Lebedev bought the Evening Standard in early 2009 and has so far made a series of moves to alter its profile.

When it initially became free, circulation was increased from less than 250,000 in August 2009 to more than 600,000, its current figure.

Lebedev also made widespread changes across the editorial team, and set about a campaign in which the newspaper apologised for its previous coverage of London.

In other news, sales talks have been extended for Lebedev's bid to buy the Independent and Independent on Sunday newspapers.