Britain's Sunday Mirror offers another--and more plausible--rationale for the event, claiming that Tehran will demand the release of up to 50 Iranian spies (previously captured by the British in southern Iraq), in exchange for the return of the sailors and marines. The paper says that the Iranian agents have been captured in recent years, by British forces operating in the Basra region.

I'll take that analysis a step further and predict that Tehran will also demand the return of some of the high-ranking IRGC and Qods force personnel recently arrested by U.S. forces. At least one of those detainees is reported to be a general officer, and a senior Iranian diplomat is also among those captives. Iran is clearly concerned that those officials could reveal vital information about Tehran's terrorist support network in Iraq and would like to get them back, to minimize further damage.