1974 British airmail to Australia from hijacked BA-870 flight; rare postal marking

1974 British airmail to Australia from hijacked BA-870 flight; rare postal marking
Hijack mail - 1974 BA870 Hijack: 18-11-1974 airmail commercial cover on [British] Midland Bank stationary, from LIVERPOOL (Great Britain) to PERTH (Australia), meter franked by red Midland Bank machine slogan mark at the period 10p overseas letter rate (for Zone C, ½ ounce letter). This letter was part of a shipment of mail originating in the UK between 16-20 Nov. & carried by British Airways flight 870, en-route to BRUNEI via CALCUTTA (India) & SINGAPORE when it was hjacked on the evening of 21 Nov. by 4 members of the Abu Nidal Organization while refuelling in DUBAI; it was then re-routed to TRIPOLI (Libya; Lebanon refused entry to Beirut); after refuelling, it flew to TUNIS (22 Nov) where 1 passenger was executed (23 Nov) following an ultimatum deadline; the next day 5 terrorists from Cairo + 2 from Holland joined the aircraft & hostages were released (45-46 on board), leaving 3 crewmen + 11 terrorists on board, who threatened to blow plane up; lacking external political support & deadlines passing, the hijackers surrendered on the morning of 25 Nov. The plane left TUNIS the next day & returned to UK with 2.5 tons of mail, where it was forwarded to its destination on the next available BA flight, ultimately arriving in Australia about a week after the original due date. Less than 50 items are known stamped with an official hijacking informational marking ( uniquely at PERTH Post Office), of which 34 were marked with the 2-line K-Type-II "DELAYED EN ROUTE | AIRCRAFT HI-JACK" instructional marking, as on this cover. The mail was delivered to PERTH general post office on 29 Nov. where the IM was applied, and the mail delivered on 2 Dec. (based on Kibble research). This is the only business-commercial cover from this event illustrated in Kibble.