The bond between the fiercely competitive Dennis and the equally driven Hamilton, the first black driver in F1, appeared unbreakable. When Hamilton signed a new five-year contract in January last year, he pledged life-long allegiance to Dennis's team.
That was despite the Spygate' scandal of 2007, Hamilton's first season as a member of the motor racing elite, when McLaren were fined £50million and thrown out of the constructors' championship for possessing technical secrets belonging to rivals Ferrari.
Hamilton and Dennis stood poised to become one of the great sporting partnerships. But while Dennis claimed he took a back seat to the McLaren operation in Australia, it is understood he may have played a significant part in the efforts to get Hamilton promoted to third at the expense of Trulli.
That is said to have caused irreparable damage to Dennis's relationship with Anthony Hamilton, Lewis's father and manager. Both the Hamiltons remain distraught that the driver's carefully nurtured good guy' image has been permanently stained by the lying controversy.
Dennis today insisted his self-enforced absence from the pit lane will be easy to take. He said: "I passed the role of team principal to Martin on January 16th, the day of the launch of our new Formula One car.
"That day I was asked many times whether I would attend the 2009 Australian Grand Prix. My answer was yes'. I duly attended it, albeit not as the person in charge of McLaren-Mercedes. It was, I admit, a strange feeling.
"The next race, the Malaysian Grand Prix, I watched on TV in the UK, an activity I found surprisingly easy. I'd expected to be more emotional about it, after an unbroken run of attending so many Grands Prix for so many years."
He went on: "I feel enormously enthused about the prospects for the McLaren Group and for McLaren Automotive, and have no qualms about leaving Martin to report to the board regarding matters connected with Formula One.
"With planned additional investment in the company of £250 million, McLaren Automotive's expansion will represent a significant investment in the UK automotive industry."
Today's announcement does nothing to ease Hamilton's immediate problems of attempting to defend his title with an uncompetitive car.
Whitmarsh has conceded that the decision to concentrate on last year's title battle, in which Hamilton beat Ferrari's Felipe Massa to the championship on the last corner of the last lap of the last Grand Prix in Brazil, meant that development of their 2009 car was delayed.
McLaren and Hamilton are now paying the price on the track. What price they have to pay for cheating in Australia remains to be seen.
