The Corporal's Wife - Gerald Seymour

A suspenseful and thrilling novel about a small British team sent into Iran to smuggle out a feisty, independent young woman named Farideh. If they are caught, they will all be executed by the fundamentalist government - the Brits because they are effectively spies and Farideh because her husband is regarded as a traitor and she has a dangerous mind of her own.
  Farideh's husband is a corporal in the Revolutionary Guard, entrapped by MI6 and held in a safe house in Austria for interrogation. His lowly position would not normally make him a target, but his job as a driver to a top general means that he knows the location of secret nuclear sites and has overheard many unguarded conversations.
  But he won't talk unless they will bring out Farideh. The SAS say it's too dangerous, but the director of the operation doesn't want to lose his prize. He assembles a little team of three ex-soldiers and one student drop-out who knows the language and smuggles them into Tehran.
  The journey out is an epic of drama and suspense, culminating in a never-to-be-forgotten run for the border. Along the way, we meet many characters, both British and Iranian, who display courage, cowardice, hatred, and love.