The sons of Lance Hart, who shot dead his wife and daughter, have described the "lifetime struggle" they endured at the hands of their father.

Lance Hart, 57, killed his wife Claire, 50, and daughter Charlotte, 19, outside a swimming pool in Spalding last July.

Watch the Victoria Derbyshire programme on weekdays between 09:00 and 11:00 BST on BBC Two and the BBC News Channel.