Britain’s pothole crisis: water, funding gaps, and the limits of patching

Britain is facing a mounting pothole crisis as water seeping into road surfaces undermines repairs and accelerates deterioration. Official figures show about 15 people a month are killed or seriously injured in crashes linked to poor roads, and projections indicate more than half of local roads could be in disrepair within 15 years, equating to roughly 106,000 miles of roadway in poor condition.

The trouble, according to engineers and industry observers, lies in the shift from hot-rolled asphalt to stone mastic asphalt, or SMA, that began in the 1990s and gained industry approval in 2000. SMA surfaces are quieter and quicker to lay and were hailed for speed and cost savings, but critics argue the method creates interconnecting voids that invite water into the material. Water, once inside, freezes during cold weather, expands, and can crack and dislodge sections of road already weakened by age and oxidation.

Surface water can spray less on SMA than on hot-rolled asphalt, but it also leaves more water in contact with the asphalt itself. The UK’s surface typically contains voids that invite water into the material, a dynamic highlighted by Mike Hansford of the Road Surface Treatments Association in discussions with The Times. He notes that water seeps into voids and cracks and can cause damage as temperatures cycle between freezing and thawing, undermining roads that are already aging and oxidized. While the potential for water damage is high, maintenance shortfalls have amplified the problem, with little preservation work carried out on many roads.

Last year, roughly 3% of major roads and 2% of minor roads underwent preservation work, down from about 7% in the early 1990s. The effects are visible nationwide: the government’s road-maintenance budget remains around £1.6 billion a year, a tiny fraction of what many experts say is needed. By contrast, repairing the pothole problem is estimated to require about £17 billion, a gulf that underscores the scale of the challenge facing highways authorities.

The M40—often ranked among Britain’s best motorways—was resurfaced with SMA in 2022 but remains in “new condition” only because it is treated with Rhinophalt, a surface-applied sealant that fills microcracks and voids every five years. The example illustrates a broader point: even well-regarded routes may stay in good condition only with intensive ongoing treatment, highlighting the long-term maintenance imperative rather than episodic patching.

Labour has pledged to fix the pothole problem and would fill an extra million potholes a year, but industry observers say patching alone will not address the fundamental drivers of road deterioration. Rod Dennis of the RAC argued that the cycle of patching up crumbling roads simply leaves the system perpetually behind the problem, calling for sustained, preventative maintenance instead of reactive repairs.

The cost of inaction is not theoretical. Projections show that without stronger, sustained investment, more than half of local roads could deteriorate further in the next decade and a half. Proponents of deeper investment point to the long-term savings from preventative maintenance, even as the current budget remains dwarfed by the scale of needed work and competing demands on public finances, including rising costs in social care. The climate and environment dimension also matters: wetter winters and more frequent freeze-thaw cycles can accelerate wear on road surfaces, increasing the urgency of resilient, well-funded programs that prioritize long-term durability over short-term fixes.

Overall, experts emphasize that the road to healthier British roads lies in systematic, ongoing maintenance and improvements that address the root causes of wear. Without decisive, funded action that moves beyond patching, the pothole problem is likely to persist—and potentially worsen—as communities contend with aging infrastructure and shifting weather patterns.