Vodafone shares took a slide following an earnings warning by the world's largest mobile operator.
For the first quarter ended 30 June, year-on-year sales rose 19.1% to £9.8bn. But the firm said the sales performance for the full year was "now expected to be around the bottom of the £39.8bn to £40.7bn outlook range" it previously forecast.
Vodafone said its outlook reflected first quarter performance, recent economic weakness and lower than expected equipment revenue.
Outgoing Vodafone chief executive Arun Sarin said, "Notwithstanding this more challenging operating environment, we continue to benefit from a diversity of assets and services, with strong revenue growth in EMAPA (eastern Europe, Middle East, Asia Pacific and affiliates), and another good quarter of data revenue growth, offsetting weakness in Spain.
"While we expect revenue around the bottom of the outlook range, our continued focus on cost reduction enables us to reiterate our operating profit and cash flow guidance for the year."