There is no doubt that F1's most surprising job move of the year so far has been former Williams chairman Adam Parr's sudden resignation in March. Since then there has been speculation that factors in F1 outside the team had something to do with it and now we have the proof. It comes straight from the horse's mouth.

Parr's departure was a shock for two reasons. Firstly because mere weeks before he left, team principal Sir Frank Williams said "if for whatever reason I couldn't come in to do my job, Adam would fill the gap." Parr seconded this by saying "I can't imagine doing anything else. I'm thrilled by the people around me, the fighting spirit we are showing. It is a huge honour to be part of that." Neither men sounded like they were ready for a split within a matter of weeks and the second reason that Parr's exit was such a shock is that he was out in a flash. Williams announced his departure on Monday 26 March and he was gone by the end of the week. It seemed stunning that someone who was the heir-apparent team principal would be gone so quickly.

Speculation focussed on whether F1's boss Bernie Ecclestone had been the driving force behind Parr's departure as the two had been involved in some very public disputes. Some suspected that Williams' co-founder Patrick Head may have even had something to do with it as there were rumours that Parr had fallen out with him. Williams put out a statement saying that Parr had left "to pursue a better balance in his life" and this put the speculation to rest somewhat. Until now.

In the latest issue of F1 Racing magazine Frank spills the beans on what drove Parr's departure. This news isn't written up as a news story in the magazine but is to be found in Frank's monthly column. It seems to put a lid on any suggestion that Parr was asked to depart as Frank writes that "Adam told me he was leaving." He adds that "there were one or two things that disturbed him in F1 - outside this company, I should add - and he came to me and said 'I've enjoyed my time, but I need a break for a while.'"

Intriguingly, Frank says that Parr "gave us plenty of warning, so we were able to prepare for his departure." It is intriguing because Parr left Williams so soon after it was announced that he had resigned. Frank adds "I don't know what he is going to do next. He's a family man and must do what he thinks is right for his long-term future. If F1 wasn't working for him, then he was right to make a move."

This of course raises the question as to why F1 may not have been working for Parr by 26 March given that just weeks before he said he couldn't imagine doing anything else and was "thrilled" by the people around him. The really big question is what were the "one or two things that disturbed him in F1." Frank has opened the floodgates again to speculation about this which is likely to lead people to think that Ecclestone was indeed responsible for Parr resigning. We can't confirm that here but what we can say is that, according to Pitpass' business editor Christian Sylt, despite Parr's departure, he is apparently still a hot topic of conversation with the F1 supremo.