Oh, not again! Iranian navy detains five Britons on yacht in Gulf

[Oberon]

Aaaand, they're released:

http://news.bbc.co.uk/1/hi/uk/8389946.stm

The Tehran correspondent summed it up quite well:

"I understand this release was agreed at the very highest level in Iran.
There is a high level of paranoia amongst some Iranian officials - they do worry that anybody in their territorial waters is spying.
The moment you take to the waters in any kind of boat off the Iranian coast, you are liable to be swooped on. They have a natural inclination to believe, particularly, anyone British must be doing something devious.
So the Iranians would have had to check that out. Then there is bound to have been a political calculation as well, over the question: "Is there any mileage in this for us?"
Obviously they have decided there is not."