David Cameron and Boris Johnson visit nursery to promote childcare . Duo left flummoxed by jigsaw aimed at teaching children three-year-old . London Mayor resorted to brute force to hammer wrong pieces together . Prime Minister gave his approval , telling Boris : 'If in doubt , wedge it in '
David Cameron and Boris Johnson visit nursery to promote childcare . Duo left flummoxed by jigsaw aimed at teaching children about seasons . London Mayor resorted to brute force to hammer wrong pieces together . Prime Minister gave his approval , telling Boris : 'If in doubt , wedge it in '