The majority of chalk streams in the country are in our area - so why have many of our MPs voted not to make companies do more to lessen the pumping of sewage into these precious waterways, and our other rivers and streams?

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

Their 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 and we have about 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, heavy or 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 rivers or the sea when this happens.

If the Lords' Amendment 45 section 141A 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?

South Cambs MP Anthony Browne rejected the amendment and voted in favour of the Bill. North East Herts MP Sir Oliver Heald did the opposite - one of only 22 MPs to do so. Both MPs have campaigned to protect chalk streams.

Ahead of the Bill heading back to the House of Lords tomorrow, Sir Oliver told the Crow:

"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."

Anthony Browne said his rejection of the Lords amendment was due to there being no plan as to how this can be delivered.

On his Facebook Page, the South Cambs MP, said: "As residents know, I care passionately about the state of our local streams and rivers, and have been campaigning hard to ensure they are clean and healthy.

"As part of that, I am strongly opposed to storm overflows containing untreated sewerage discharging into rivers. It is disgusting and environmentally damaging and needs to end.

"That is why I am glad the Government is introducing a comprehensive package of measures to eliminate the discharge of untreated sewerage into rivers, and I was delighted to vote for them as part of the Environment Bill.

"However, I will begin by commenting on Lords’ Amendment 45 to the Environment Bill, which was voted on this week, and about which a number of constituents have contacted me.

"The Government has inserted a range of amendments to the Environment Bill to address the concerns I and other MPs have raised about storm overflows. I was pleased to vote in support of Amendment (a) to Lords Amendment 45, which passed by a margin of 265 votes for to 202 votes against.

"Concerns have been raised that section 141A, tabled by the Duke of Wellington in the House of Lords, was removed from Amendment 45."

Explaining that section 141A seeks to demonstrate progressive reductions in harm from sewage, he added: "This all sounds admirable, and indeed is something I support in principle. But the trouble is that the Duke’s amendment came with no plan as to how this can be delivered and no impact assessment whatsoever.

"Some might argue that a plan is not essential, that one can be formulated afterwards. I would be sympathetic to this point of view if we were talking about a simple, inexpensive endeavour. But in eliminating storm overflows, we are talking about transforming a system which has operated since the Victorian era.

"The practical problem is that across the UK there is just one system of pipes that takes both rainwater and sewerage from homes, rather than separate systems for rainwater and for sewerage.

"The preliminary cost of this national infrastructure change is estimated to be anywhere between £150 billion and £650 billion."

"The Government’s view was that it would have been irresponsible to have inserted this section in the Bill given that it was not backed by a detailed plan and thorough impact assessment. It would have been the equivalent of signing a blank check on behalf of billpayers."