Pensioners in Oxfordshire say they have been left high and dry by Thames Water's new payment system for people whose homes can't have a water meter.

The company plans to introduce a council tax banding-style system for thousands of home- owners.

One 83-year-old woman from Didcot, who did not want to be named, told the Oxford Mail she faced an annual bill of £266, up from £245, even though she lived alone, because she did not have a meter and lived in a three-bedroom house.

That is £100 more than her son and daughter-in-law pay for water at a four-bedroom house in the same town.

Peter Makin, 48, of Trent Road, said Thames Water had tried several times to install a meter at his mother's home but was unable to do so.

He said: "Since my father died three years ago she has lived alone and her demand for water has dropped. Now she will be charged as if all the bedrooms were occupied. If she lived in a single-bedroom property, she would only have to pay £200.

"How many more pensioners are being penalised for living in their family homes by themselves? Even the district council gives a tax rebate for single occupancy."

Chalgrove pensioners Jill and Derek Merrick, who live in a three-bedroom house, asked for a meter 18 months ago but were told they could not have one, because the only suitable site was in their neighbours' drive.

Mrs Merrick said: "The upshot was our neighbours could have one installed and we couldn't.

"Why do we have to pay the same as someone with a family, when we only use a fraction of the water?"

Not only pensioners are affected. Liz McGowan, 39, from Kidlington, also lives in a three-bedroom house which cannot have a meter.

"It just feels like a bit of a rip-off," she said.

"I'm going to write to my MP and Ofwat about the new billing system. I have friends who pay half as much."

Thames Water spokesman Don Sharples said: "We're very interested to hear about these cases and we will investigate what we can do.

"As more and more people apply for water meters, we're going to have to investigate what sort of solutions we can provide.

"We're trying to apply a system which will cover the majority of people and for the most part it's working out OK."

He added that billing people according to the number of residents at a property left the company open to fraud.