Morning Star editor Richard Bagley wrote to Prime Minister David Cameron today to protest against the exclusion of the people's paper from key talks on the future of press regulation.
Mr Cameron and Culture Secretary Maria Miller are hosting a major meeting tomorrow with media editors and publishers to discuss the future of press regulation following the Leveson report.
But the Morning Star is not invited.
The snub to Britain's only socialist national daily follows the exposure of a vicious Whitehall-wide boycott by government departments, where mandarins have barred the Star from their regular media subscriptions.
Mr Bagley told Mr Cameron: "Dear Prime Minister, I am writing to express my disappointment that the Morning Star has not been invited to the major meeting on press regulation."
He added: "In the interests of media diversity, it seems to me that the Morning Star should have been invited.
"It is Britain's only socialist daily paper and it is owned by a co-operative society with a management board which has representatives from trade unions making up more than half the membership of the TUC.
"Perhaps you could suggest how the Morning Star can be brought into future discussions on the follow-up to the Leveson report.
"Could you also clarify whether or not the Morning Star would be bound by any future media regulation regime if it has never been consulted on the issue or involved in any of the discussions."
A Downing Street spokesman was challenged today about the failure to invite the paper to the meeting. But he simply replied: "Speak to the Department for Culture, Media and Sport."
A spokesperson for the culture department then told the Star: "Space is limited at the meeting and it will be attended by editors and proprietors from the main national newspapers."
Mr Bagley also wrote a similar letter of complaint today to Culture Secretary Ms Miller.
Labour MP Grahame Morris said: "Mr Cameron has indulged in rhetoric about protecting a diverse, free and independent press, yet he seems to have no qualms about denying the Morning Star access to his meeting.
"The Morning Star is one of Britain's longest-established national newspapers," he emphasised.
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