Preston City Council has pledged to reduce its reliance on a controversial weedkiller which is currently used to treat parks, pavements and roads in its patch.

The herbicide glyphosate was classified by cancer experts at the World Health Organisation (WHO) as being “probably carcinogenic to humans” back in 2015 – although it remains legal to sell and distribute in the UK and elsewhere.

The WHO’s International Agency for Research on Cancer said that its findings were based on “limited” evidence of cancer in humans – from real-world exposures to the product – and “sufficient” evidence of cancer garnered from experiments in animals.

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The city council has already cut its use of the chemical by a third over the past five years, but has now committed to continue that reduction while it assesses “the feasibility” of using alternative weedkillers – including by trialling pesticide-free products. Meanwhile, the authority will also investigate whether it is possible to stop spraying glyphosate in parks and recreation areas “in the immediate future”

The multiple moves to cut back on its use in the city follow a call by the Liberal Democrat group on the authority, which secured cross-party support after a slightly diluted version of the party’s demand was agreed at a recent meeting of the full council.

Initially, Ingol and Cottam ward councillor John Rutter had proposed in a notice of motion that the authority stop using glyphosate within a year and phase out the use of all pesticides on council-owned land by 2025.

However, the ruling Labour group amended his proposal, warning that the suggested timeframes were impractical.

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Cllr Rutter said that while he would ultimately like greater clarity about the speed at which there will be a reduction in glyphosate use in Preston, he was encouraged by the “open and pragmatic” approach that council officers had taken in engaging with the issue – and by the “wide agreement that the use of these nasty chemicals should be reduced”.

Cabinet member for the environment and community safety Freddie Bailey said that while he understood “the principle” of the Lib Dems’ original call, “at this moment in time, there isn’t an alternative product that produces the same results”.

“If we banned glyphosate products within a year and…all weedkilling products by 2025…it could damage our paths and our pavements, parks, roads, walls and our buildings. More weeds means more litter is trapped across the city,” Cllr Bailey said.

He also told the meeting that the city authority was paid – under an agreement with Lancashire County Council – to treat public highway areas for weeds twice a year and warned that if it stopped doing that work effectively, County Hall would be likely to end the arrangement and itself use glyphosate to do the job anyway.

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Members heard that any alternatives to the product are likely to be more expensive, but Lib Dem group leader John Potter cautioned against the risk of a catch 22 situation developing between different levels of local government.

“What we can’t have is the county council saying, ‘We’re leaving it up to the districts’ and the districts saying, ‘We can’t [change anything], because the county isn’t paying us any money’ – [and so] nothing happens.”

A report by a task group at County Hall, which was set up to assess the maintenance of the public realm in Lancashire, last month recommended that arrangements be made between the county council and district authorities to trial herbicides other than glyphosate – but concluded that it was ultimately for the districts or parishes doing the work to decide which products to use.

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