The North Korean government may deny their existence, but photos taken from space have revealed in unprecedented detail the concentration camps that are used imprison more than 200,000 citizens.

Men, women and children are forced to work seven days a week as slaves and eat 'rats, frogs, snakes, insects' and even faeces to battle starvation in the camps.

Previously there have been blurred images taken by satellite but new detailed pictures from South Korea's Unification Ministry allow a closer look at the sites - and also prove they have grown.

Experts say the tens of thousands of prisoners at the camps are often taken from their homes or in the street for supposed 'political crimes' rather than actual misdemeanours.