In a statement issued by the Mayor's office, Livingstone said the decision was great news for Londoners but added: "Of course, the exclusivity for morning distribution has not been lifted and we will reserve our right to press for this to be removed."
Transport for London's tender notice inviting bids for the distribution of a free afternoon newspaper was published this week.
The OFT released its findings today after the conclusion of a two-year investigation into the deal Associated Newspapers made six years ago with London Underground. The investigation was sparked by a complaint from Daily Express owner Richard Desmond, who has long said he wants to launch a paper to rival Associated's Metro and Evening Standard.
The OFT said the exclusive deal granted to Associated went beyond impartiality by effectively locking out any competition.
"The OFT had concerns that by excluding rivals' newspapers from stations 24 hours a day, despite the fact that the Metro is only distributed in the morning, the exclusivity granted by these agreements went beyond what could be objectively justified," the OFT said.
Associated has responded by offering to give up its afternoon and evening distribution slots, allowing London Underground, Network Rail and train operators to re-tender the rights and earn fresh revenue from any future deals.
Desmond is reported to have a free paper, called London-i, ready to launch. News International is also believed to be resurrecting plans for a free paper, drawn up six years ago.
Express Newspapers said: "We are delighted with the successful announcement from the OFT. We look forward to being the successful bidder for the contract and will declare our next step in due course."
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