Scottish Water subsidiary Business Stream has increased its foothold in the English non-domestic water market, following a series of contract wins.
The water retailer said it had secured £100m worth of new contracts since the business retail market was deregulated south of the border in April.
They include water supply deals with Debenhams and Southampton Airport.
Business Stream has been expanding its operations in an effort to increase its share of the £2.5bn English market.
Last year, it bought Southern Water's business retail arm, taking on more than 100,000 non-domestic customers across Kent, Sussex, Hampshire and the Isle of Wight.
The Edinburgh-based company also opened a new office in Worthing, West Sussex.
The deregulation of the English market has enabled 1.2 million businesses and public bodies in England to choose their water supplier for the first time.
Business Stream recently announced it had won places on two major public sector water frameworks - Laser and the Crown Commercial Service (CCS) - giving it access to markets in England worth hundreds of millions of pounds a year.
Business Stream chief executive Jo Dow, said: "We've been extremely targeted in our approach, focusing on customers who are looking for a trusted partner to advise and support them on their water and wastewater requirements.
"We feel that this offers us a point of differentiation from our competitors."
The company is a wholly-owned subsidiary of Scottish Water with its own board and independent management team.