The deadly witch doctor's plant sweeping Britain

Thorn apple has trumpet-shaped flowers and spiky fruit, and grows up to 3ft tall. It has poisonous flowers and seeds and can cause hallucinations.

Originating in America, it has been growing in Britain for more than 100 years - but a dramatic rise in sightings has been reported in the past two months.

Jill Turner, a toxic-plants expert at Kew Gardens in South-West London, believes its spread could be due to bird-feed manufacturers adding its seeds to their mix.

She said: "The number of photographs sent in by members of the public asking for identification of the strange fast-growing plant that had appeared mysteriously in their gardens suggests it is becoming much more widespread.

"It probably appreciates the warmer and drier summers we have been having recently."

Thorn apple is also known as Jimson weed, and its scientific name is Datura stramonium.

It is smoked as a mind-altering drug in some countries, and Native American witch doctors use it in ceremonies and to induce coma in unsuspecting victims.

In Peru it is the main ingredient in a stupefying drink.

To stop the weed spreading, the seed heads should be snipped off before they dry and burst open.