National Highways sticks to runoff plan targets despite funding questions

National Highways has told MPs that it reaffirms its aim to improve around 250 sites where road runoff provides a high risk of polluting the environment, despite being set a lower target in the Road Investment Strategy (RIS 3) and advice from its regulator  that it should come clean about what can really be afforded.

Appearing before the Transport Committee last week, National Highways’ Chief Operating Officer Duncan Smith said: “We’re very pleased to say that we’ve been given funding in RIS 3 to mitigate those locations where they have the highest  potential risk to the environment.”

“So, it’s not saying they are polluting, but based on the receiving watercourse and some of the topography and dynamics of the road that they are supporting, those are ones that are the highest priority for us to invest in. And we think that by 2030, we will have improved around 250 of those locations to ensure that the receiving watercourses are protected.”

The commitment in the new RIS is to mitigate 190 – 250 high risk sites, implicitly by 2031, while the company’s 2030 Water Quality Plan sets the target of 250 sites.

The RIS target is subject to “reviewing a deliverability plan by the end of 2027/28” and “includes those outfalls and soakaways mitigated during Road Period 2 and 2025/26”.

This is less ambitious than the 2030 plan but higher than what the company said it could afford, as quoted in its regulator’s November 2025 advice on its draft business plan:

“National Highways estimates that between 110 and 130 mitigated assets will be delivered from the allocated budget as part of this programme in RP3.” 

“So, it’s not saying they are polluting, but based on the receiving watercourse and some of the topography and dynamics of the road that they are supporting, those are ones that are the highest priority for us to invest in. And we think  that by 2030, we will have improved around 250 of those locations to ensure that the receiving watercourses are protected.”

A National Highways spokesperson said the company estimated that by the end of 2030 it will have mitigated around 250 sites.

However, the Office of Rail and Road (ORR) has estimated costs per asset mitigated had more than doubled to between £900,000 and £1.2m against a budget of £159m. 

It stated: “This means National Highways will not deliver ~250 outputs by 2030 which it previously proposed and committed to in its 2030 Water Quality Plan. 

The company estimates that between £186m and £294m would be required to deliver all the mitigated  assets by the end of RP3. National Highways should seek to work with the department to manage expectations where it has previously committed publicly to deliver a bigger programme and the reasons this is no longer feasible.”

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