Johnson: 8/10 D (Too early to judge really)
May: 6/10 E (Swallowed by Brexit despite potential)
Cameron: 8/10 B (Lost marks on social guff)
Brown: 4/10 E (Created his own mess and got swallowed up)
Blair: 7/10 A (Full marks on foreign policy)
Major: 9/10 B (Poor party leader, actually a good PM)
Thatcher: 9/10 A (Best PM)