Japanese Knotweed is capable of doing serious damage to buildings, lifting concrete and undermining walls and foundations if left to its own devices and it has long been a criminal offence to deliberately plant it in the wild.

However, you are perfectly entitled to grow Japanese Knotweed in your garden if you wish; you just can’t let it spread beyond the boundaries of your own property.

In fact, anti-social behaviour rules apply to a homeowner who lets the plant get out of control, under new Home Office guidance.

So, if you find Japanese Knotweed invading your garden from next door, you can now make an official complaint to the local authority and/or the police.

If the neighbour responsible ignores an order to control the plant, they will be committing an offence resulting either in an on-the-spot fine of £100 or prosecution, which could bring a £2,500 fine.

Surveyors hate the stuff, so much so that mortgages have been refused on properties where it has been spotted growing – even in a next door garden.

Here’s the experts – the RHS – to tell us how to identify it and what to do