Kenneth Bae, 44, who was born in South Korea but is an American citizen, has been held since November when he visited the North Korean city of Rason.
He was tried in the country's Surpreme Court on charges of plotting to overthrow the government but the exact nature of his alleged crime has not been revealed.
More top news
Darlington has endured deep spending cuts in recent years and Mrs May has a tough job of convincing parents in the Labour seat.
Two "despicable" men who posed as good Samaritans before stealing from a man as he had a stroke are being hunted by police.
April showers and a cold northerly wind