Katharine Hamnett has spent the morning handing out fliers that read: ''London Fields Caution Danger Unacceptable Risk of Biohazard''. Last week she discovered that the local wild-flower meadow had been sprayed with Roundup, a glyphosate-based herbicide.

"I've been giving leaflets out to women with babies because I was so concerned," she says, attacking a plate of pad Thai. "I thought they were young single mums. Then I looked at their clothes and thought, 'F---. Nothing but Isabel Marant. A touch of Chloé, a bit of Saint Laurent.' And I realised they were City lawyers taking their baby breaks. Which is even better, because they can help me out with the legal stuff."