Her motivation came after she saw amenity workers spraying the herbicide in London Fields, very close to her house. She has since printed leaflets and posters warning people not to walk or picnic near the sprayed area in the wildflower meadow.
On her website Hamnett, who was awarded a CBE in 2010 for services to fashion, says she was "outraged by the indiscriminate, unnecessary and unannounced use of Monsanto's 'Roundup' herbicide in our local park" and "horrified" at the prospect of picnickers eating with their hands near the sprayed area.
But the council’s corporate director of health and community services Kim Wright, said the product had been declared "safe and environmentally friendly" by government, and it is used by councils across the country for weed control as well as being widely on sale to the public. She added that it was not used on grass or shrubs in Hackney.
Hamnett is chairing a public meeting in London Fields Church Hall on Saturday featuring the former director of Friends of the Earth in England, Wales and Northern Ireland, Keith Tyrell, director of Pesticide Action Network UK, London green MEP Jean Lambert,
The meeting had to be moved from a pub on the edge of the park after the campaign grew in just a few days. It has also attracted Green MP Caroline Lucas’s support.
An online petition to Hackney Mayor Jules Pipe calling for glyphosate to be banned across Hackney – the petition does not specify commercial or council use – has been signed by 87 people since launching yesterday.
The use of glyphosate is controlled in the UK but amenity professionals complain that not all users, including amateurs, apply it properly. Non-chemical approaches have been trialled and have been successful in some areas but have also proved more expensive.
The Amenity Forum was created to share best practice and encourage training in the field. Delegates at its last conference in November heard from Telford & Wrekin Council parks and open spaces team leader Chris Jones who criticised the government for a lack of joined-up thinking on pesticides and budget cuts.
"Now there is only glyphosate left to help keep weeds under control and many replacements for banned chemicals are costly and give limited control," he said.