SES Water has been challenged to continue improving after it was criticised by a watchdog for the “sharp rise” in complaints it received from customers.

The company, which has hundreds of thousands of consumers across Sutton and parts of Surrey, came under fire from the Consumer Council for Water (CCWater) after publishing its annual complaints report.

It laid out the extend of aggrieved people picking up the phone or writing in about their supply - one of three cited to have underperformed by the watchdog.

And while there was a 15 percent reduction in complaints received by SES Water during the first six months of 2018/19, they are still being urged to do better.

Sir Tony Redmond, CCWater’s London and South East chair, said: “These figures give us reason for optimism but SES Water remains a long way from where we would like it to be compared to rest of the industry.”

“We want to see further improvements over the next few months to ensure customers have even less reason to contact the company with a problem.”

SES Water says it’s making “fundamental changes” to systems and processes as it has reached the half-way stage of its two-year “transformation programme” in a bid to improve customer experience.

Since it was launched last January the company says it has seen complaints drop by nearly 45 percent between April 2018 and the previous year.

And they are also reportedly on track for a 20 percent drop between March 2019 and the same time last year.

Head of retail services Dan Lamb said: “We want the most satisfied customers in the country so providing high-quality service and reducing complaints is very important to us.

“We are now at a three0year low of 9.5 complaints per 10,000 properties, and during 2018 we reduced complaints by 39 percent and saw a 17 per cent reduction in unwanted contacts.

“The improvements we are making have also seen us increase our position in the Service Incentive Mechanism (SIM) league table this year and achieve our highest ever billing score.

“In our business plan for 2020 to 2025 we aim to go even further and achieve upper quartile C-MeX performance by building on all the good work we’re already doing.”

CCWater is a non-departmental public body, independent of both Government regular Ofwat and water companies, which represents consumers across England and Wales.

It seeks to provide impartial advice or advocacy for consumers who are unhappy with the services they are being provided.