The Iranian government remains insistent that its seizure of the South Korean chemical tanker Hankuk Chemi on Monday, just days before high-level diplomatic negotiations between the two countries, is purely coincidental.

Nobody seems to be buying this line. There are too many precedents involving Iran's seizure of ships to further political and diplomatic aims.

This unique approach by Iran to hold ships on an allegation of breaching maritime law to force diplomatic negotiations has been used to surprisingly good effect in the past.