The majority of chalk streams in the country are in our area - so why have many of our MPs voted against making companies do more to lessen the pumping of raw sewage into these precious waterways?

Chalk streams are the UK’s equivalent to tropical rainforests, according to the Herts and Middlesex Wildlife Trust.

Its website states: "They support a huge variety of rare and vulnerable wildlife. Some of our most iconic and well-loved species - like the water vole, wild brown trout and mayflies - depend solely on these rivers to survive in Hertfordshire."

Chalk streams are globally rare - there are around 200 chalk streams on earth. Almost all are found in the UK, with around 10 per cent in Hertfordshire.

What was the vote on?

On Wednesday last week, there was a vote on a proposed amendment to the Environment Bill, regarding storm overflows.

Storm overflows protect properties from heavy rainstorms and prevent sewage from overflowing into streets and homes.

They are part of an older type of sewer system which carries surface water and foul water in one pipe.

During a storm event, prolonged rainfall can rapidly increase the flow in a combined sewer and cause it to become overwhelmed. Storm overflows are designed to release excess storm water - into streams, rivers or the sea - when this happens.

If the Lords' Amendment 45 section 141A - put forward by the Duke of Wellington - became law, sewerage undertakers in England and Wales would have to demonstrate progressive reductions in the harm caused by discharges of untreated sewage.

Raw sewage was pumped into waterways 400,000 times in 2020, according to Environment Agency figures.

How did our MPs vote?

The commons vote was 268 to 204 in favour of the Environment Bill - with 22 Tory MPs rebelling, in favour of the Duke's of Wellington's amendment.

Stephen McPartland and Nadine Dorries voted in favour of the bill, therefore rejecting the amendment to make it illegal for water companies to continue to be able to pump raw sewage into waterways.

Sir Oliver Heald did the opposite, saying firms had a "duty to reduce sewage overflow". Bim Afolami couldn't attend the debate on Wednesday last week due to a family funeral, and and Richard Fuller also abstained.

Mr Afolami said: “Unfortunately, I was unable to attend or vote on the Environment Bill debate on Wednesday as I was at a family funeral.

"We are very fortunate in Hitchin & Harpenden that we have a large number of local chalk streams, including the Ver, Lea, Mimram, Purwell, Oughton and Hiz.

"I am committed to protecting these rare habitats and have been working hard to ensure that they have the right protections against inappropriate water usage, environmental threats and future development.

"The amount of sewage discharged by water companies into our rivers is unacceptable and ministers have made it clear that sewage discharges from storm overflows must be reduced. The Environment Bill as drafted is tougher than existing powers and will deliver reductions in the harm caused by storm overflows.

"The Duke of Wellington’s amendment, while well-intentioned, is already delivered through the many measures of the Environment Bill.

"We must also be pragmatic in relation to the calls for complete elimination of storm overflows. That would require lots of new sewerage systems – initial assessments suggest total elimination would cost more than £150 billion – and could result in sewage being discharged into the streets instead during extreme rain.

"I continue to support action to reduce sewage discharges and will work with Parliamentary colleagues to deliver stronger powers to tackle these, but in a way which avoids significant costs for consumers and the risk of sewage in the street during floods.”

North East Herts MP Sir Oliver Head was one of only 22 Conservative MPs to vote against the Environment Bill.

Ahead of the Bill heading back to the commons tomorrow, Sir Oliver told the Comet: "I am a longstanding campaigner on river water quality and have eight chalk streams in the North East Herts constituency - Upper Rhee, Ivel, Rib, Quin, Ash, Beane, Mimram and the Lea.

"They need more water flow, restoration and less pollution. These rivers are special and the public support improving them. There have been improvements, but much more needs to be done.

"The Environment Bill puts in place a duty on Government to produce a plan to reduce sewage going into rivers and for water companies to report regularly on the amount of sewage overflow use.

"I would like to see a duty on water companies to comply with the new national plan and reduce sewage overflow and other discharges.

"The Bill continues in Parliament with the House of Lords looking at it again tomorrow and I hope agreement can be reached. I know ministers are listening."

Stephen McPartland didn't respond to the Comet's request for comment, but he has tweeted indicating his reasons for voting as being the cost and time it would take to revamp the sewers.

He said: "Pleased to vote for a plan to reduce sewage in our rivers. I wish we could stop it immediately, but it would cost up to £650 billion and be forced back into people’s homes for years until our 200-year-old sewage system was fully replaced."

North East Beds MP Richard Fuller told the Comet: “I did not support the Government in the division on this amendment last week.

"I have previously supported my colleague, Philip Dunne MP, with his efforts for a Private Members Bill last session and am working with him to achieve progress on this issue with this amendment.

"This particular amendment is likely to come back to the House of Commons for a further vote later this week and I have joined with Philip Dunne to urge the government to make further comprises to enable greater progress to be made.

"I am hopeful that the government will bring forward such a compromise amendment that can be supported.

"I have been disappointed by the campaign responses by some environmental pressure groups and by a concerted effort at misinformation both about the government’s intentions and the current status of storm overflows and untreated sewage discharges.

"For example, some have suggested that this bill will for the first time permit discharge of untreated sewage from storm overflows whereas in reality this already occurs and the debate is about how far to restrict current practices.

"As I have stated above, I am hopeful that the government will make further progress with a new amendment when this comes back to the House of Commons later this week.”

Mid Beds MP Nadine Dorries was contacted by the Comet, but did not respond.

The Bill will be revisited in the Lords today, before another Commons vote tomorrow.