Andy Burnham to launch ‘structured dialogue’ on issue at Commonwealth summit in Antigua and BarbudaAndy Burnham will ask countries affected by Britain’s role in slavery to help shape an expected formal apology, Downing Street has indicated, arguing that their input is indispensable in crafting an enduring message.The prime minister was en route to the Commonwealth heads of government summit (Chogm) in Antigua and Barbuda, which begins on Tuesday.