I think Steyn is wrong on this one, and that's probably the first time I've ever thought that.
I'm guessing it was very much a one way conversation with the Iranian ambassador. "We're going to give you a day or two to let them go. If you do, we won't ratchet up the rhetoric and embarrass you publicly. If you don't, than we and the United States are going to be extremely unhappy." So the "tradoff" was that the Brits don't force the Iranians to look like they're caving it to westerners, but the Brits get their guys back quickly.
If Teheran really wanted to play hardball, they'd have kept them for a few weeks to embarrass the Brits. They didn't.
Tho Steyn has a major point about fleet streets willingness to accept the mistreatment of their own citizens while squalling over islamists with panties on their heads.
I havent followed this event since it occurred during my vacation, but perhaps the lack of resolve on the part pf the British government and the lack of backup by America was Meant to embolden them.
Lets face it, Iran and Syria have to be dealt with. Politically it may be best to coax them into crossing the line.