This text explains why beers like Smithwick's came into existence:
ALE AND PORTER.See what I mean? Pale Ale was the only English beer to have any popularity in Ireland. It wasn't a cheap beer. No surprise then that local breweries took to brewing their own version.
Strangman, Davis and Co. of Waterford, represent a vast and influential trade in Ireland, by the exhibition of two casks of Ale and Porter. It would be rather a difficult matter to express any opinion as to the character of the liquor from the appearance of the vessel in which it is contained; besides, I must admit my total incompetency to pronounce a judgment, in any shape, upon an article which is so popular, and so largely consumed. It is only necessary to say, with respect to the Irish brewing trade, that it is recovering from the serious injury which it sustained by the temperance movement, and the renewed depression in the years of famine; that its home consumption is very little interfered with by English importation—Bass' pale or bitter Ale being the chief article which finds anything like favour in this country; and that the Irish brewers, on the contrary, do a large and increasing business in England, and with foreign countries. Cork Porter, Drogheda Ale, and Dublin Stout, are well known and highly appreciated out of Ireland. The firms of Beamish and Crawford, and Lane, of Cork, and Guinness of Dublin, are amongst the most eminent in the United Kingdom. Abbott of Cork also enjoys a high reputation. There are, besides, several prosperous breweries in the principal towns throughout the country. Kinsale, Bandon, Fermoy, Youghal, Dungarvan, and many others in the neighbouring counties, have each their thriving brewery.
"The industrial movement in Ireland, as illustrated by the National Exhibition of 1852" by John Francis Maguire, 1853, pages 64 - 65.
Many years later, looking for Irish styles, someone decided Red Ales were a particluarly Irish style. Rather than just crappy key Pale Ale. Given time, style hunters have probably decided Watney's Red was a great example of English Red Ale. Just a shame it died before they had chance.