Vodafone Ireland said there was a 12 per cent increase in customer numbers in the fourth quarter of the year. But most of these are pre-paid customers who provide lower revenue than those on contract.

The numbers using its mobile phone service rose to 1,704,000 in the three months ended March, an increase of 182,000 on the same quarter a year earlier. This allowed the company to maintain its market share of 58 per cent.

But the firm said its focus would be on deriving value from existing customers rather than acquiring new ones.

Some 72 per cent of users were pre-paid customers while 28 per cent were bill-paying customers.

Just 1 per cent of its customer base in the Republic was inactive compared to 11 per cent in Britain and 8 per cent in the Netherlands, a spokeswoman said.

The company did not release an average revenue per user figure but said it would be included when final results for the year are issued on May 28th.

Meanwhile, shares in its parent group slumped yesterday. Vodafone shares hit four-year lows just above 100 pence before closing 4.9 per cent higher on the day.