The editors of the Daily Mirror and Sunday Mirror have been made redundant "with immediate effect" after the company announced it was moving to a seven-day operation.
Richard Wallace and Tina Weaver were told this morning they were losing their jobs and have been replaced Lloyd Embley who had been editing The People.
The move to a seven-day operation comes after tabloid rival The Sun launched a Sunday edition following the demise of the News of the World.
Critics described the move as "brutal" and a "shock", but Trinity Mirror said it was a "further step towards creating one of the most technologically advanced and operationally efficient newsrooms in Europe".
I'm delighted to appoint Lloyd to the position of editor of the Daily and Sunday Mirror. He is an accomplished editor who has done a first class job on improving the performance and profile of The People, having spent several years on the Daily Mirror in a senior executive role. Both Richard and Tina leave with our best wishes for the future and our thanks for the extremely valuable contribution they have made to the Daily Mirror and Sunday Mirror during their tenure as respective editors.
The company plans to appoint a weekday and a weekend editor to work under Mr Embley and a new editor for the People and said it will launch e-editions of its papers for tablet computers.
Mr Wallace was the Sunday Mirror's deputy editor until taking the top job at the Daily Mirror in 2004, having worked as a showbiz reporter at the paper previously. He replaced Piers Morgan at the helm of the tabloid when Mr Morgan was dismissed after publishing photographs - later shown to be fakes - which purported to show British soldiers abusing Iraqi prisoners.
Ms Weaver became editor at the Sunday Mirror in 2001 after working her way up as a reporter on the now defunct Today and the Daily Mirror.
Former Daily Mirror editor Roy Greenslade said the sacking of the pair came "as a shock to them and their staff".