'It's not going to kill you but you're going to wish it did' - Getting close to Alnwick Poison Garden's most painful plant

It's hard to say definitively which is the most dangerous plant in Alnwick Poison Garden.

The Guinness Book of Records says Ricin Communis, with one of its beans able to kill several adults. Yew tree berries can kill in under half an hour, while strychnine can tear muscle from the bone.

But when it comes to the garden's most painful plant to come into contact with, there's no competition. The Gympie-Gympie, known in its native Australia as the stinging tree, is a distant relative of the nettle.

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And while nettles can leave you with a nasty rash and itching for days, that pales in comparison to what its Aussie cousin can do. A sting from the Gympie-Gympie has been compared to "hot acid poured upon you as you're being electrocuted and set on fire at the same time."

Dean Smith, guide at the Alnwick Poison Garden, said it was "awesome" to have such a powerful plant in the garden. He said: "If you get stung, it's not going to kill you but you're going to wish it did."

The tree sits in a glass case at the far end of the Poison Garden, the only clue from the outside that its heart-shaped leaves can inflict serious damage. However, when it arrived in the North East in July last year, gardeners wore full Hazmat suits to get it into its current position.

It has since become one of the most popular exhibits, with many exhibiting a morbid curiosity in the plant's tremendous potency.

Anneka Thompson is one of the guides who waters the gympie-gympie three times a day, between public tours of the garden. Their gloved hands open the door slightly, and spray water into the case through the smallest gap possible.

There's also a humidifier inside to keep the conditions, which are monitored by a moisture meter, optimal for the stinging tree. Anneka said: "The biggest thing when you're doing this is to remember not to sneeze.

"Any disruption to the air can dislodge hairs on the leaves. Getting stung is bad enough but inhaling it is even worse!"

There are more spines on each leaf of the plant than hair follicles on the human head. And just one injecting its neurotoxin into the bloodstream causing "the most enormous pain that comes from a plant".

Despite the plant's potential to cause agony, watering it now is "just another chore," for Anneka. They continued: "At first, I was a little bit nervous.

"But as with the rest of the plants, the more you're around them, the more you know to keep yourself safe. It's just another chore now, like emptying the bins!"

Guide Dean Smith added: "This is the one that has the most risk assessment, as you can imagine, because of how easy it would be to inflict such a huge amount of pain. I feel confident that we have got it here because the precautions have been taken."

And it's a good job - treatment for the pain can involve stripping off a layer of skin with a hydrochloric acid solution, dousing the affected area in lighter fluid and setting it alight, or amputation. However, it's not all bad news.

Researchers from the University of Queensland are studying the toxins in the plant, in the hope that it can lead to the development of new pain treatments. The toxins interact with nerves, but need assistance to do so, and researchers now hope that they can "switch off" the pain mechanism in the development of new painkillers.