A Somerset MP has accused South West Water of “operating like a mafia” during a debate in Parliament.

Ian Liddell-Grainger, the Conservative MP for Bridgwater and West Somerset, called the company “the nation’s filthiest and leakiest supplier” and demanded an urgent debate in the House of Commons.

Penny Mordaunt MP, the leader of the House of Commons, said Mr Liddell-Grainger would have an opportunity to put his concerns to the relevant minister later in the autumn.

Mr Liddell-Grainger raised the issue in the Commons yesterday (Thursday September 7), following a previous Westminster Hall debate on water pollution in mid-July.

He said: “This House, as the Leader of the House is aware, takes a dim view of bullying – unless it is by me.

“She will be shocked to learn that Britain’s worst water company has now resorted to thuggery and strong-arm tactics to silence parliamentarians and the press.

“I refer, of course, to the Pennon Group, which includes the nation’s filthiest and leakiest supplier, South West Water.

“Its chairman, Gill Rider – who worked for the Cabinet Office and so is used to leaks, I suppose – has hired City lawyers to threaten the press and parliamentarians if we speak out against the company.

“She is running a mob that has convictions for polluting rivers, pays its top gun criminal bonuses and, despite the wettest July on record, still has a hosepipe ban.

“It is operating like a mafia. This is absolutely appalling.

“May we have an urgent debate in government time on these ruddy water companies, who are blackmailing their customers and parliamentarians to stop the truth coming out?”

Mr Liddell-Grainger was recently selected to contest the new Tiverton and Minehead constituency at the next general election – much of which is served by South West Water.

Ms Mordaunt responded that Mr Liddell-Grainger should put his concerns directly to environment secretary Thérèse Coffey MP at the next scheduled Defra questions in the House.

She said: “My honourable friend has raised issues related to that particular company many times in business questions, and the whole House can sense his frustration and anger with what is happening.

“I suggest that he may wish to raise the matter with the relevant secretary of state on October 19.

“He is an experienced parliamentarian and will know how he can achieve a debate.”

Mr Liddell-Grainger – who has represented his current seat since 2010 – has used the protection of "parliamentary privilege" to make his comments. MPs cannot be sued for libel for anything they say within the House of Commons - and the media may report the comments.

South West Water responded, saying: “South West Water is an open and transparent business that welcomes scrutiny from all stakeholders, including parliamentarians, media and of course our customers. However, we have a responsibility to protect any member of our 3000 strong team, who are working hard to deliver for customers, the region and our environment.

"We work in collaboration with all our parliamentarians as we deliver on our investment commitments.”