Last week I opened a Backbench Business debate in the House of Commons on the government’s Strategic Policy Statement to Ofwat.

Despite the dry title, this is an incredibly important issue – as the Strategic Policy Statement is the primary mechanism through which the Government influence the water regulator, Ofwat, to refocus priorities for capital expenditure by the water companies in England for the next five-year pricing period, from 2025 to 2029.

Since privatisation, Ofwat’s remit has focussed mostly on ensuring supply of quality drinking water while keeping down household bills, with much less regard to investment in water quality. But given Ofwat’s unique position as the economic regulator, it has to approve capital investment. So I have been pushing for this focus to be not only on household bills and water supply, but also on the environmental impact that water companies have.

With the rising cost of living, none of us wishes to see bills rising sharply, but equally, if water rates are set so low as to preclude necessary capital investment in water quality, we will simply kick the can down the road for another five years and the problem of sewage discharges into our rivers will be harder to solve and more expensive to fix.

In fairness to water companies, there is no quick fix for six decades of underinvestment in water infrastructure – despite the posturing some party political campaigners continue to make. Water companies are also not solely responsible. For example, when new houses are built, developers do not have to pay towards the cost of water and waste water infrastructure. Agricultural runoff is also a significant issue.

Even when water companies do come up with plans to improve sewerage, it takes years to build significant new infrastructure, even after a potentially lengthy planning system process.

Earlier this week I visited the largest such project in the UK – the Thames Tideway project – 25km of new sewers under London, which will remove 37 million tonnes of the 39 million tonnes of sewage currently discharged legally each year into the Thames. This transformative project is being delivered at only around £20 per annum per household, but it does however illustrate well both the high cost and the length of time involved in delivering a transformational project to improve water quality - namely £4.9 billion and 11 years from securing planning to becoming operational.

So a long term solution requires long term campaigning, and I shall be keeping up the pressure. Next month I shall be hosting a public meeting with Severn Trent Water about efforts to clean up the River Teme from Knighton to Ludlow, where real local progress is underway.