Metro's website operation is to be folded into Mail Online, raising questions over parent company Daily Mail & General Trust's long-term commitment to the print edition of the commuter freesheet.
It is understood that Metro.co.uk's digital operation – which after significant investment has seen a 300%-plus surge in browsers over the last year to more than 22 million a month – will be subsumed within Mail Online.
Insiders say that the move is not a cost-cutting measure, no jobs will go as part of the integration, and that the Metro brand will somehow be retained within Mail Online.
Steve Auckland, the Metro managing director, said that Metro.co.uk has cracked the 3 million daily unique audience barrier which has given a "glimpse of the audience potential of the website".
"However, the potential to accelerate this growth and monetise it is best served by the Mail Online team at this moment in time," he said. "It will free the rest of the business to concentrate on reinvigorating Metro."
Auckland has said that he aims to focus on a "print-first" strategy for Metro.
However the move further adds to speculation that DMGT is seeking to sell the print title in the medium term.
Auckland was brought in to drive the commercial operation of the newspaper in a restructure late last year.
Metro made £80m in revenue in the year to the end of September, a 10% year-on-year fall at least in part due to a tough comparison with the advertising boom around the London Olympics in 2012.
Auckland was previously responsible for whipping DMGT's regional newspaper operation Northcliffe Media into shape ahead of a sale of the business to David Montgomery's Local World.
A number of observers see a parallel with what Auckland has been brought back to do with Metro.
One City source says that while there is no official sale mandate out on Metro, it is understood that DMGT would not consider it to be off the table if an approach was made to buy it.
A significant issue for any would-be buyer is the status of Metro's London Underground distribution contract.
The seven-and-a-half-year deal, which runs into 2017, sees the title made available in 250 tube stations and 14 bus stations across the capital.
Any suitor would need to be mindful of the possibility of not regaining the contract.
One source says that the ideal buyer for the title would be Alexander Lebedev, as the morning title would allow the oligarch to effectively lock down the capital in terms of free newspapers during the day with the Evening Standard coming out in the afternoon.
"It makes a huge amount of sense for Lebedev, he would be the perfect buyer, if he wasn't looking to sell [the Independent] himself," said the source.
DMGT has had the Boston Consulting Group in looking at a range of options for its newspaper and web operations, with Metro considered to be a significant focus.
Earlier this week Metro lost Martin Ashplant, head of digital content at Metro.co.uk, to London business title City AM.
City AM, which is headed by former Metro International executive Jens Torpe, is aiming to ramp up its nascent digital presence to match US rival Business Insider which is thought to be launching a UK-focussed operation later this year.
"The opportunity for a fresh take on business news online is huge in the UK," said the City AM editor, Allister Heath. "The success of sites like Businessinsider in the US shows what can be done."
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