The London club confirmed in a statement that the pair would take charge "immediately" .

Mourinho's profile has already been removed from the club website and Chelsea confirmed in a statement: "The club is delighted that in Avram we have an experienced man who can come in immediately at this difficult time to help deliver our objectives.

"In Steve we have a Chelsea man and he will be a crucial part of the management team going forward.

"Avram and Steve have our full confidence and support."

Earlier on Thursday, Mourinho ran out of the training ground in Cobham, Surrey, at about 10.45am.

He hid his face in his trademark trenchcoat as he dashed past a crowd of reporters and photographers waiting for him.

He refused to comment on his departure from Chelsea before getting into the back of a black saloon car and being driven off.

Only the previous night, a glum-looking Mourinho, along with a number of senior players, attended a screening of 'Blue Revolution' - a new documentary about the Abramovich years.

However it is believed Mourinho had earlier contacted five senior players in the afternoon to inform them of his departure and by midnight the entire first-team squad had learned he was going.

The club's chief executive Peter Kenyon, chairman Bruce Buck, and Chelsea owner Roman Abramovich's key aide, Eugene Tenenbaum, were called to an emergency meeting at Stamford Bridge on Wednesday night to discuss the emerging crisis.

Mourinho's departure was eventually confirmed when they posted a statement on the club's website.

Former players and managers said they feared Chelsea could now struggle after the departure of the self-proclaimed 'Special One'.

"I'm absolutely astounded at what's happened," former Chelsea captain Ray Wilkins told Sky Sports News.

Another former Chelsea player, Gavin Peacock, told BBC Radio Five Live: "I think that half the team will have been affected badly and it's going to be hard to get that team spirit that Jose managed to manufacture."

Mourinho, 44, has been at loggerheads with Abramovich since their disagreement over the lack of funds to sign players during last January's transfer window.

Mourinho's reluctance to play Andriy Shevchenko and the Russian's desire to bring in Grant from Portsmouth to work with the misfiring striker only served to heighten the tension.

The Portuguese - whose £5.2 million a year contract was due to expire in 2010 - has been dismayed by the constant watering down of his authority.

Abramovich's decision to recruit Dane Frank Arnesen from Tottenham as director of scouting and youth development in September 2005 was compounded further by the arrival of Grant.

But their dismal start to the new Barclays Premier League campaign and their 1-1 draw with Rosenborg in the Champions League on Tuesday only served to heighten the problems and Mourinho decided he had reached the end of the road.

He had won every domestic honour since his arrival in England in the summer of 2004 but the Champions League eluded him.

Although he won the trophy with Porto in 2003, Chelsea were twice knocked out of the competition at the semi-final stage by Liverpool during his tenure.

Grant and Clarke will not have an easy start in their new roles - their first game in charge on Sunday is against defending champions Manchester United at Old Trafford.