It's supposed to be an amicable parting. He and Benham the chairman are old city mates from their hedge fund days..
He's supposed to have lined up the Rayo Vallecano manager Paco Jemez to take over - supposedly, it's all to do with their recruitment policy - Benham is a believer in a moneyball/stats approach to player recruitment, Warburton isn't.
"Speaking to the BBC, he said: 'He (Benham) wants recruitment to be based more on mathematical modelling and statistics allied to normal scouting methods.
'Matthew's a very smart individual. His company is based on football analysis and data and we've used that over recent months. There will be more emphasis on that area.
'It's been very amicable but it's two different philosophies. He's the owner and that's the direction he wants to take the club in.' "
The chairman has very specific idea's he wants to achieve and that includes being in the new stadium by 2017-18....but they have their very own 'archway metals' type fighting the CPO.
If you want to know why he believes so strongly in his data driven approach (which as an analyst I find compelling) you should read this:
http://www.theguardian.com/football/blog/2015/feb/22/brentford-mathematical-modelling-denmark