Looks like a single stem of Horsetail before the leaves appear. Could well be growing through from your neighbour's garden, suggest you remove rapidly.

Oh! Flippin Heck, I hope not, I think I will give a knock on their door, never had a problem in all the 25yrs since we have been here?
Thanks for the info :o))

I would say that MG is spot on. Let it come into leaf, a slight crush and paint it with Glyphosate and beat a swift visit to your neighbours.

It is 2ft high but no leaves, I hav already snap the stems down.

Looks a little bit like hippuris vulgaris grows in ponds and damp ground :) I've had it before but had no luck with it :)

Yes, I thought it was the pond plant too. I've had horsetail in my planters (bought topsoil grrrr) and it starts off ever so small. I'm with Dan. Does your neighbour have a pond or bog garden near the fence?

Just to clear up the misunderstanding. Two different species. Horsetail (commonly wrongly called marestail which is a pond weed) is the toughest weed to eliminate from a garden.

Ok Jimmy gotcha thanks.

It looks like Horsetail Reed (Equisetum hyemale)

The stems of mine are quite thick? Unlike the thinner type I had where I used to live years ago.
My neighbour is building a pond, they may have bought some in ready for when they finished it? I haven't spoke to them yet but will.
I've read this is very invasive Awww!

I'm sorry this is Horsetail Reed (Equisetum hyemale) as Tugb. and others have already said. Even if your neighbour's pond is built no-one in the right mind would intentionally put Mare's Tail into it!

Not too bad confined to a pot, but be sure to prune off the knob-shaped spore cases that form on some stems before they open.

Horsetails are a big and ancient family. The semi-aquatic Equisetum hyemale and japonicum are pretty much harmless; they are commonly sold as pond plants.
You only have to worry about E. arvense, the common invasive, pernicious weed of allotments and gardens. You can't mistake this as it has feathery fronds unlike the ornamental aquatic species.