BEYOND the bottom of our garden, on the shingly banks of the River Tees, there is a tall and rather handsome alien. But it’s a foreign menace, coming over here, stealing our space and poisoning our children.

It is giant hogweed, which this summer is basking in notoriety as the tabloids’ latest horror obsession – there has been a nasty rash of stories telling how its sap causes a nasty rash of blisters and burns. This week, even a Great Dane called Ellie from Sheffield has its nose turned red raw when it inhaled too deeply of the hogweed.

This danger, of course, is nothing new – although this is the first summer I have seen so many specimens growing so imperiously in the shadow of Croft bridge.

I remember covering Middleton St George parish council in the early 1990s when councillors were spending a small fortune on pesticides to rid the riverbank of this foreign invader. They said it had come over as a stowaway on a timber ship from the Baltic, jumped onto Stockton quayside, was now marching up the Tees and it was their job to tackle before it grew too tall.

"If you wait till the hogweed is fully grown you'll need Red Adair," one councillor said memorably, referring to the famed oil well firefighter.

The first giant hogweed seeds were sent by collectors from the Caucasus Mountains, in Russia, in 1817 to Kew Gardens in London.

Its proper name is Heracleum mantegazzianum, after Heracles, the Greek god famed for his strength, and Paolo Mantegazza, a 19th Century Italian anthropologist who was the first person to extract cocaine from coca leaves.

Mantegazza's hogweed is truly impressive. Towering over the riverbank, you can feel it bursting with energy as it unfurls its enormous leaves and shoots up to 15ft in just a couple of months. It is topped with huge umbrella-shaped flowerheads that look brashly sculptural and which the Victorians regarded as beautifully ornamental – “one of the most magnificent Plants in the World,” said a seed salesman in 1870.

The Gardener’s Magazine of 1835 said: “We do not know a more suitable plant for the retired corner of a churchyard, or for a glade in a wood.”

But giant hogweed was not content simply with retired corners and secluded glades. It wanted world domination, and even as The Gardener’s Magazine went to press, it was on the loose – it was first recorded growing wild in Cambridgeshire in 1828.

Those Victorian gardeners must have known that the giant hogweed had toxic tendencies, but they seem not to have mentioned it, and it wasn’t until the summer of 1970 that the plant revealed its true colours, when hospitals started filling up with blistering children.

The hogweed’s sap contains furocoumarins – chemicals that make the skin so hypersensitive to sunlight that it burns very easily. So dangerous is the plant that it is an offence punishable with two years jail under the 1981 Wildlife and Countryside Act “to cause it to grow”, and a landowner can be issued with an asbo if he fails to tackle it on his property.

Should you get the sap on your skin, wash it off immediately, and keep out of the sun. The best advice, though, is to avoid it like you would a smotheration of stinging nettles, and although its tempting, don’t use its 15ft hollow stalk as a gladiatorial weapon or giant peashooter. Just stand back and admire it, for it is mightily impressive.