Silverstone with its fast straights would seem to be an ideal track for KERS to provide a slingshot out of the corners to gain a few Miles per Hour for the full length of the straight.
The BMW and Renault teams are not so sure and have opted not to use KERS at Silverstone.
Ferrari has continued its development of KERS and now has a new lighter version which will be used by both Massa and Raikkonen.
McLaren will be trying out both options on Friday with Kovalainen running with KERS and Hamilton seeing how the car goes without it during practice one and practice two. There are not many hard braking areas where the KERS can be effectively recharged.