SHELL-MEX & B.P. LTD.

S321 was used before and after the Second World War, followed by S322 until 1963 and then S323. Stewart gives the funnel a wider red band than other sources. A photograph of B.P. Engineeer confirms S322. The pre-1963 flag was yellow with a green cross, a red shell in the canton and a white shield with black BP in the fourth quarter. Rosanoski considers the S323 flag erroneous: Loughran’s narrow central red–yellow–green triband may result from yellow being printed through to the top.

The museum flag is dated 1955–1967. António Martins-Tuválkin relates its red and green vertical stripes to Mexico and the company name. Rosanoski questions this, suggesting instead a combination of Shell’s red, white and yellow with BP’s green, red, yellow and white; he also suspects a printing error in Loughran’s intervening full-height yellow.

Ridley Chesterton describes a white–yellow–white flag. A black-and-white photograph of Caerrnarvon shows the funnel’s yellow band wider than its white bands, which might also apply to the flag if it existed. Rosanoski doubts the flag, suggesting it may have been inferred from the funnel, but retains it because Chesterton explicitly describes it.

A postcard shows an equal-stripe variant. Martins-Tuválkin suggests simplification by the postcard artist or careless sewing of the real flag; Rosanoski questions giving the postcard precedence over the maker.