[...] it is only occasionally that the Isle of Man is seen, bearing north-west from Southport. It is supposed that when this island is visible, blowing weather may be expected.
—Peter Whittle, ‘Rivington Pike’, in Marina; or, An Historical and Descriptive Account of Southport, Lytham, and Blackpool (Preston: Peter and Henry Whittle, 1831), p.41.
The Snaefell, the highest mountain on the Isle of Man is at an altitude of 2037 feet above sea level, and at a distance of 72 miles from the very edge of Southport’s pier; from its summit the horizon should appear to be at 55.26 miles, just a bit shy of the 72 miles that separate us.
However, there are indeed atmospheric conditions that could render the Snaefell visible: Refraction, which is particularly finicky over water, combined with other thermal phenomena, can indeed make such a sighting possible; without getting too technical, there have been many instances of landmasses separated by more than twice our 72 miles suddenly becoming visible under the right conditions: a 1933 survey in California, for example, observed Mt. Shasta from Mt. St. Helena, and they are at distance of 192 miles.
So keep an eye to the horizon, and have a tall ladder handy, for good measure.
N.B: When this was published in Facebook’s “Southport News” group, an accompanying poll with 91 votes yielded as results that while 70% of the voters thought it impossible to see the Isle of Man from Southport, 29% of responders claimed to have had seen personally. A member even had a photo, which is the one published here.