<text>  Michael Vaughan believes Alastair Cook is clearly bitter, and must set aside his own World Cup disappointment for the good of his England team at the start of their Ashes year. Cook claimed on Wednesday that Englands decision to replace him as captain with Eoin Morgan, at the 11th hour before the global tournament in Australia and New Zealand, was proved probably wrong by subsequent events. England made an embarrassing early exit at the hands of Bangladesh, before the knockout stages were under way. Alastair Cook was replaced as Engtlands one-day captain before this years World Cup . Former captain Vaughan interprets Cooks remarks as a sign that he is still struggling to come to terms with what happened after losing his 50-over role because of his continued poor batting form. Cook will nonetheless lead England in three Tests against the West Indies, on a tour starting early next month, before returning home to face first New Zealand and then Australia this summer. BBC pundit Vaughan said: Hes clearly bitter. I think thats a bad mentality to have, when you think hes going to be back leading the team in a couple of weeks time. Cook led England to a Champions Trophy final on home soil two years ago, and the top of the world rankings, but their recent one-day international record under him deteriorated. Vaughan added: Alastair Cooks last six captaincy jobs in ODI series for England, he lost every single one. The only series theyve won was away in the West Indies, when he wasnt the captain. Michael Vaughan claims Cook is bitter about the decision to replace him as captain . Cook could only watch from afar as England beat only Scotland and Afghanistan in their World Cup campaign under Morgan, but he sensed they were shell-shocked and in need of real leadership. Vaughan argues Cook must move on, and start scoring prolifically again - as he has for the vast majority of his record-breaking career. I dont think its great that the captain comes out and criticises the leadership of the captain that takes over - but hes clearly bitter. Hes got to clear that out of his head, because its so important that by the time he gets to the West Indies England need him scoring runs. He has to score runs in the Caribbean; he has to get runs against New Zealand - so by the time the Ashes arrive in July, no one is talking about Alastair Cooks position in the Test team. He hasnt scored a hundred in any format of the game for two years. That has to change in the West Indies. 