Wigan Album

If I was on army manoeuvres and I came across that flag I would give it a wide berth, or better still if I had the ammo I would blow it and whatever it was being flown from to bits - that flag has nothing to do with Britain or the Union!

'BP' British Petroleum aka Deutsches Erdöl

The reason why the Union flag is displayed upside down on the advertisement is that the company was a German one. BP or British Petroleum was actually a German company selling petrol or motor spirit and oil to Britain before WW1, they wouldn't have had many sales of their products if called Deutsches Erdöl

*** "Despite its name, the British Petroleum brand name was originally created by a German firm as a way of marketing its products in Britain. During the war, (WW1) the British government seized the company’s assets, and the Public Trustee sold them to Anglo-Persian in 1917. With that, Anglo-Persian had an instant distribution network in the UK, including 520 depots, 535 railway tank wagons, 1,102 road vehicles, four barges and 650 horses."

*** From here. https://www.bp.com/en/global/corporate/who-we-are/our-history/early-history.html

Also read. https://archive.commercialmotor.com/article/23rd-november-1916/1/the-meaning-of-motor-spirit

Well spotted Cyril, Its design is all wrong. The broad white stripe on the
upper left quarter of the Union Flag should be above the red stripe and
the thin white stripe. Many people refer to it as the Union Jack, but as far
as I know, It is called the Union Jack only when it is attached to the Jack
staff on a Royal Navy ship.

This sign seems to appear for sale quite frequently amongst the memorabilia on sale on The Bangers and Cash TV programme,