Guinness lager is a let-down for Diageo

Diageo might be the world's biggest drinks company but it admitted it is struggling to turn Guinness into a lager.

Guinness Black Lager, a version of the stout which gives it the fizz of lager, was launched in the US in 2011 and in Ireland last year, but sales have been "disappointing". There are no plans for a UK launch.

Deirdre Mahlan, the chief financial officer, said: "When people taste it they really like the liquid but you have to educate the consumer … actually finding the right trigger can sometimes take a bit of time."

Overall sales of Guinness were down and the group lost share as it refused to cut prices in tough markets. But Diageo's huge roster of spirits were much stronger, with US drinkers in particular snapping up premium vodkas Ciroc and Ketel One. Diageo sales rose 5 per cent to £6.04bn in the half year to December. Its shares rose 24p to 1,877p.