Violent criminals were included among those wrongly released from jails in Great Britain due to administrative mistakes. London prisons featured heavily in the top ten instances of prisoners freed inadvertently over the past three years – Pentonville (six times), Wandsworth (five) and Belmarsh (five) were among the most common. BBC home affairs correspondent Danny Shaw said although official statistics have emerged before about this subject, this was by far the most extensive data released so far.