Re above remark that this is often sung in a Welsh accent: surely this would be by association with the tune, an ancient Welsh war song.   

"Harlech (Welsh pronunciation: [ˈharlɛx]) is a town and seaside resort in Gwynedd, within the historical boundaries of Merionethshire in northwest Wales, lying on Tremadog Bay" ... "'Men of Harlech' or 'The March of the Men of Harlech' (in Welsh: Rhyfelgyrch Gwŷr Harlech) is a song and military march which is traditionally said[1] to describe events during the seven-year siege of Harlech Castle between 1461 and 1468.[2][3] Commanded by Constable Dafydd ap Ieuan, the garrison withstood the longest known siege in the history of the British Isles". Wikipedia

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