Frank Lampard left Chelsea to join Man City in 2014GETTY

Frank Lampard left Chelsea to join Man City in 2014

That’s according to journalist Rob Beasley, who has written a biography about the Special One called Jose Mourinho: Up Close and Personal.

In it, Beasley explains how Chelsea’s contract renewal policy all but forced Lampard out.

He was offered far more cash at Manchester City because the Blues didn’t like handing big deals out to players over 30.

The Chelsea fans are split over whether they love Frank LampardGETTY

The Chelsea fans are split over whether they love Frank Lampard

Frank Lampard angered some Chelsea fans when he decided to leave the clubGETTY

Frank Lampard angered some Chelsea fans when he decided to leave the club

Beasley wrote: “Frank Lampard’s defection to Manchester City in the summer of 2014 infuriated the hierarchy at Chelsea and left Mourinho desperately disappointed.

“The stumbling block was that Chelsea had recently introduced a policy concerning players who were aged over 30.

“The’d decided that once they’d passed that magic number, all new contract would then be for one year only.

“Chelsea offered Frank Lampard a poor deal; Manchester City offered him a very good one”

Rob Beasley

“The problem at Stamford Bridge was that Chelsea tended also to reduce the terms for these one-year contracts dramatically, asking players, even living legends like Lampard, to take huge pay cuts into the bargain.

“Ultimate, that’s why Lampard left in 2014.

“Chelsea offered him a poor deal; Manchester City offered him a very good one.”

Source: http://www.dailystar.co.uk/sport/football/556215/Frank-Lampard-Chelsea-left-club-Man-City