First-quarter earnings fell more than a quarter at GlaxoSmithKline, the pharmaceuticals group, on the back of generic competition and tougher economic conditions in the US.

Earnings per share rose 3 per cent in cash terms to 26.3p, but were down 28 per cent at constant exchange rates on sales 5 per cent lower at £6.8bn before accounting for the sharp strengthening of the dollar against sterling, the currency in which GSK reports. Pre-tax profits fell 31 per cent to £1.9bn.