An unlikely mish-mash of international pop stars descends on Guinness's St James's Gate brewery and sundry other Dublin venues tomorrow for the second annual "Arthur's Day". Manic Street Preachers, Tinie Tempah and that bloke from The Killers who can't decide whether or not to grow a beard are among those bound for the Irish capital, where they will spend the evening serenading the world's favourite stout. If such a juxtaposition of facial hair and egos sounds far-fetched consider that last year they had Tom Jones sweating out his hits alongside Dizzee Rascal and Kasabian.

In Ireland, Arthur's Day – the anniversary of Arthur Guinness signing a 9,000 year lease on St James's Gate in 1759 – is being pitched as a sort of secular St Patrick's Day, a long overdue acknowledgement of the centrality of Guinness to Irish life. Which may have made sense if Brandon Flowers was being flown in to belt out Mr Brightside, in, say, 1958. Nowadays, of course, Guinness is the liquid equivalent of a plastic bodhrán or one of those strap-on Leprechaun beards you can buy in tourist shops: though outsiders regard it as a key component of their authentic Irish "experience", for natives it is less a national symbol than a relic of bygone times.

Guinness remains one of Ireland's favourite beers. While sales fell 5% in 2009, market share actually increased as the pub trade slipped deeper into a recession-fuelled slump. Anecdotally, however, Guinness drinkers belong overwhelmingly to two categories: older people and tourists. Step into a fashionable city centre bar in Dublin, Cork or Galway and you'll see the Celtic Tiger generation – those who haven't yet departed for Australia or Canada at any rate – relaxing not over filthy pints of the "black stuff" but coffee, imported lagers and craft brews (after years of false starts, micro-brewing is finally taking off in Ireland).

There has been some cynicism about Arthur's Day, particularly outside the capital where Guinness is regarded less as an Irish emblem than a specifically Dublin one (imagine if every visitor to the UK went around extolling Fuller's London Pride as a quasi-mystical distillation of the British soul). With the economy orbiting the drain, you've also got to wonder if this is a good time to reinforce the stereotype of the booze-marinaded Paddy. In the same month Taoiseach Brian Cowen was accused of giving a radio interview at least two sheets to the wind is it wise to applaud a multinational drinks conglomerate such as Diageo for trumpeting the country's supposed spiritual relationship with a particular brand of porter?

When Dublin's futuristic Samuel Beckett Bridge opened recently, one waggish UK journalist suggested designer Santiago Calatrava was inspired by the famous Guinness logo. In fact, the structure's distinctive arch was based on Ireland's national emblem, the harp. What ought to be a symbol of Irish ingenuity is now synonymous with a tipple which, if chugged to excess, can make you feel you've been quaffing lard. Come the big day, "Uncle" Arthur will surely understand if some of us aren't clinking tankards in gratitude.