It is May 1977. Idi Amin, the President of Uganda and claimant to the Scottish throne has been banned from attending the Commonwealth Summit in London, but has declared that he will be there. The police and army are placed on armed alert.
Meanwhile, far and away in the centre of excellence known as Bristow Sumburgh, the Operations Manager is planning a joke on his friend and opposite number at Airport Operations. He sends him a telex (remember them) advising that Idi Amin and his entourage is attempting to enter UK via Scotland in a Norwegian charter aircraft. Be extra vigilant. He attaches the discreet Special Branch Answerback code. Well satisfied he sits back to await his friend's reaction.
Completely coincidentally, an innocent Norwegian registered light twin contacts Sumburgh ATC and advises them that he is inbound. The airport police swing into action and Special Branch London are informed, they duly inform the Foreign Office who recall Lord Carrington, the Foreign Secretary, from a Cabinet Meeting to deal with the emergency.
On landing at Sumburgh our innocent Norwegian is surrounded by blue flashing lights and the total complement of the Airport Police. The aircraft is searched, the crew questioned, but nothing untoward is found.
After a brief lull the blue flashing lights arrive outside Bristow Operations. We are asked if we know anything about a telex. The Ops Manager assures them that nothing is known at all, but a brief search uncovers a carbon copy of the telex in the waste bin. Our man is removed to the airport "slammer".
The Managing Pilot, T W-M, manages to scrape enough money together to pay the police bail and thankfully all parties recognise that this has been a joke that has backfired and no further official action is to be taken.
A few days later the Ops Manager receives a letter from Alan Bristow, the gist of which is:
"Bloody funny (name redacted), but if you do it again you're fired".