USA celebrates 250 years of independence

Temperatures soar as America gathers to celebrate its 250th birthday. Ken Burns talks about his new series about The American Revolution and tells us what he believes the pursuit of happiness really means. In a valedictory interview, Sir Keir Starmer looks back, and forward, as he prepares to leave office. And we look at how a new NHS scheme aimed at rewarding people who walk thirty minutes a day might work.