John Wyndham

The Day of the Triffids

1951. Penguin, 1963.

The only thing we could see on the broad stretches of grass were two or three little groups of triffids lurching southwards. Somehow or other they had contrived to pull up their stakes and were dragging them along behind them on chains. I remembered that there were some undocked specimens, a few tethered, but most of them double-fenced, in an enclosure beside the zoo and wondered how they had got out

Security at Regent's Park Zoo, and everywhere else, has gone to pot following a global disaster, and the plants - seven-foot-high walking carnivores with a deadly sting, originally cultivated for their yields of high-grade oil - are now intent on exterminating the human race. (And you're worried about GM crops?)