Hi,
Is it absolutly necessary to have 60% in your undergraduation like B.sc , B.a to get admission in top u.k uni.. for Mba...
Even if you have a solid Gmat and good amount of work ex. in managerial level... but a lower gpa...
Some advise please...

Each school will publish its requirements. Solid.. Good... these are rather general terms. On average, you need to be above average.

HI,
I have 720 in gmat & a 2.2 gpa... with a 3.5 yrs work.ex till date. My major concern is gpa... it might prevent me from geting a good b-school..

That depends on the school, and what else you have to show.

You mean i can still hav a chance if i can put up a good application...

Oh yes, more than a chance. The GMAT is more important than the GPA.