GMB union members at Anglian Water are to be balloted on whether to take strike action in a dispute over pay.

The union's central executive council approved the ballot in the wake of a 2.5pc pay offer, accusing the company of 'corporate greed'. Unite members will also be balloted.

However, an Anglian Water spokesman insisted the unions' position did not reflect the mood of the majority of its staff - and it gave a reassurance that the impact on consumers would be paramount if strike action went ahead.

'It is early days to talk about contingency plans but our starting point would be to avoid any effect on customers,' he said.

Eamon O'Hearn Large, the GMB's lead officer for water, said this year's offer had followed a pay freeze last year.

'This offer was rejected by members in a ballot vote. However Anglian Water refused to go to ACAS and imposed the offer,' he said. 'Members then voted overwhelmingly in an indicative ballot for industrial action and to move to an official ballot. We are currently making arrangements for the ballot and we will announce the date shortly.'

He described the company's position as a 'classic case of corporate greed'.

'Anglian Water is a natural monopoly being used as a cash cow funnelling billions into offshore tax havens while paying little corporation taxes while treating its manual workers appallingly,' he said.

A spokesman for Anglian Water, which manages water and water recycling for over six million customers, said: 'We don't feel either union's position reflects the mood among the vast majority of our staff. The unions appear to want an argument about a pay review which happened six months ago.

'Our pay award this year was 2.5pc, plus an extra bonus of £250. All employees at Anglian Water already enjoy private healthcare and high quality pensions.'

He said their own survey of all staff showed a 71pc positive response to the offer.

'This ballot for strike action will achieve nothing for staff,' he said.

'It's difficult to imagine our customers would support action like this when many of them haven't seen a pay rise of any sort, not to mention a special bonus, private healthcare and a great pension.

'We know things are financially challenging for both our staff and our customers at the moment. That's why we made the offer we did, and paid the bonus that we did, so that we could support staff as well as being able to promise that we'll keep customer bills below inflation for the next five years.'

Concerning tax, he said: 'Last year we paid £167 million directly and indirectly in different taxes. Our Corporation Tax bill is reduced by specific government incentives, but it is deferred not avoided. This is encouraged by the government to stimulate long term investment in infrastructure and jobs.

'We are investing around £2 billon on the region's infrastructure between 2010 and 2015, much of which is spent in our region and with local firms.'