The UK’s biggest water company ramped up competition last Thursday with plans to poach high-use customers from suppliers in other parts of the country.

Thames Water, which currently serves 14 million mainly residential customers in London and parts of the Home Counties, has been granted licences to sell to businesses throughout England, Wales and Scotland.

The water will still come from a company’s regional provider but Thames will compete on price and other parts of the offer, such as customer service and fixing leaks.

The entry of the UK’s biggest supplier is seen as an important step in making the commercial market more competitive.

It means Thames will, for the first time, be able to target high-use businesses in England and Wales, such as large supermarkets, breweries and heavy industry, while it will be able to sell to any businesses in Scotlandregardless of how much water it uses. The move comes after the government last year changed the rules to open up competition to more businesses by allowing those with facilities in England and Wales that use five million litres of water a year to shop around for water. Previously only those that had used 50 million litres a year were eligible.

In Scotland, all businesses can already shop around for water in this way.

The government’s plans are expected to see it open up all businesses to competition in this way in 2017, creating a £2.5 billion (€3 billion) nationwide market.

Piers Clark, director of the newly-formed Thames Water Commercial Services, said: “Securing these licences marks our official entry into the competitive water retail market. We will offer eligible business customers the simplicity of having one bill and one service provider.”