Person from Wigan.
Nothing to do with the large number of pies eaten in Wigan but to do with a miner's strike in the 1920's when all the pits in WIgan and Leigh went on strike. The Wiganers went back and broke the strike, the "Leythers" continued to strike and got better pay and conditions. Therefore the Wiganer's had to "eat
humble pie"... so it's a term of abuse from Leythers to Wiganers. The hostility between the two towns stretches back hundreds of years to
the civil war when Wigan was Royalists and Leigh were Parliamentarian and continues to this day.