How well are Britain's borders patrolled and defended at a time when the authorities are battling to stem the flow of illegal immigrants coming across the Channel and tightening national security because of fears of a terrorist attack by extremists returning from fighting in Syria and Iraq? Allan Urry assesses the vulnerability of our ports, struggling with cuts to Border Force personnel and problems with a computer system that was supposed to have identified all those coming into and going out of the UK. The programme reveals how security checks on cargo are being compromised and hears concern about the gaps in surveillance of our coastline. Producer: Emma Forde Reporter: Allan Urry.