The flavouring of whiskies has been one of the most commercially successful, talked-about and, for purists, controversial trends in the global spirits industry in recent years.

But the Scotch industry itself has been overwhelmingly content to sit it out.

These new tipples - mostly targeted at a younger, more female consumer base - usually involve sweetening or flavouring whisky or bourbon by adding honey, herbs, spices, citrus fruits or berries.

Last year, production of Jack Daniel's Tennessee Honey reached one million cases, becoming the first flavoured whiskey to achieve the milestone.

More recent launches include the first ever flavoured Irish whiskey, Bushmills' Irish Honey. This was followed by the release of two extensions of Pernod Ricard's Paddy Irish Whiskey brand with honey and spiced apple variants.

At the time of the launch, Pernod Ricard Irish Distillers said it wanted to "challenge the traditional perceptions of whiskey".

Other new drinks include Crown Royal Deluxe, a Canadian blended whisky matured in maple-toasted oak barrels, and Ballantine's Brasil, a lime-flavoured "Scotch" that is carefully described by Chivas Brothers as a "spirit drink" and directed largely at the Far Eastern market. Peter Moore, global brand director for Ballantine's, has predicted that demand for flavoured whisky will continue to grow and the category is not just a "short-term fad".

Particularly controversial was last year's launch by Bacardi of Dewar's Highlander Honey, which is marketed in the US as a "Scotch whisky infused with Scottish heather honey filtered through oak cask wood".

Strict Scotch Whisky Association (SWA) guidelines and European Union law stipulate that no ingredients apart from caramel colouring and water can be added to Scotch whisky. But, according to the SWA, no rules have been breached if the resulting concoction is labelled as a liqueur or spirit drink.

Despite the controversy, drinks industry analysts believe such creations are poised for further growth in the coming years. The Scotch industry is likely to watch from afar, content that the traditional marketing cues that have served so well over the decades may need occasional refreshing, but you overhaul them at your peril.