Mobile phone giant Vodafone has suffered a half-year loss after being forced to write down the value of its operations in Italy and Spain.

The British company made a loss of £1.98bn, compared with a net profit of £6.68bn a year earlier, caused by fewer calls being made in southern European countries and a competitive UK marketplace.

In the UK, revenues were down by 2.1% and underlying profits fell by nearly a third as the higher cost of retaining smartphone customers also hit home.

Shares were also 3% lower on Tuesday, despite the company announcing a £2.4bn dividend from US joint venture Verizon Wireless, of which £1.5bn will be returned to shareholders.

Vittorio Colao, the group chief executive, said in a statement: "We have continued to make progress on our strategic priorities over the last six months, with good growth in data and emerging markets in particular. In the short-term, however, our results reflect tougher market conditions, mainly in southern Europe."

Colao maintained the company was "very positive" about the future however, making much of Vodafone's "2015 strategy" which will see new approaches applied to European pricing models and focussing on growing its exposure in emerging markets.

"Fundamental to the success of this strategy will be an ongoing enhancement of the consumer and enterprise customer experience through continuous investment in high speed data networks, and an increased drive towards standardisation and simplification across the group to maximise cost efficiency and accelerate execution," he concluded.