The UK’s largest water company, Thames Water, has said around 300 of its jobs could be cut.
In a separate statement, the GMB union said it was told of 140 redundancies at the firm.
Consultations on cutting 89 retail and 39 digital jobs will begin, the union added.
The retail side of Thames Water deals with business customers. But there will be no changes to how customers are served, the company said.
Recruitment for a range of digital roles, including in programming, cyber security, data and insights, started in January this year.
More than half of the roles under review have yet to be filled, Thames Water added.
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A company spokesperson said: “We are consulting on a proposal which could lead to the potential loss of around 300 roles.”
Compulsory redundancies will be minimised where possible, through redeployment and voluntary redundancy, they said.
“Frontline colleagues will not be impacted by these proposed changes, with roles at risk primarily in our retail and digital functions as well as some other areas.
“Change does mean difficult decisions and we are focused on supporting our colleagues throughout the process.”
The utility company currently faces debts of up to £14bn and risked collapse over the summer when it looked unable to meet repayments.
It eventually secured backing from investors including Omers, the Canadian pension fund, and the Universities Superannuation Scheme (USS).
The Thames Water spokesperson also said: “The last year has been an extremely challenging year for the business and we continue to take a rigorous approach to financial discipline throughout the company in order to operate within budget.
“We need to make more difficult but necessary decisions to ensure we continue to deliver to our budgets. That’s why today we’ve announced a range of measures to reduce our costs further and become more efficient.”
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The GMB union said it will fight to minimise compulsory redundancies and “make sure our members get every penny they are due”.
GMB national officer, Gary Carter, said: “Thames Water has danced with the devil and now workers are paying the price. In the 40 years since privatisation, we’ve seen virtually no investment, systematic asset stripping and billions of public money drained from the system to fill already building shareholder and fat cat coffers.
“As a result, Thames is on its knees and water workers are losing their livelihoods.”
Roughly 8,200 people are employed by Thames Water.