Persicaria? Could be invasive & difficult to remove...

I would go with that. I almost looks like the aquatic variety in the way it is spreading.

look at Polygonum persicaria. That's what I know it as.
its a native wild flower here in the UK. it may well have been renamed.

OK thanks for the info. Yes, it definately wants to spread like wildfire.

I've had a quick look and nothing immediately comes up about it being toxic. but that doesn't mean it isn't. So definitely don't chew on it ;o)

it seeds freely too.

lol I wasn't thinking of eating it but my cat might have other ideas.

I think it looks a pretty plant. Like the leaves and the flowers.
I’ll be googling it now.

Looks very much like Persicaria longiseta?

'Poisonous Plants in Britain', MAFF 1984 doesn't give it a separate section but adds it to the entry about rhubarb. It says it has an acrid juice that can cause skin irritation and gastric problems if consumed in large quantities.

But it also says that cases of poisoning are very rare something the 'International Poisonous Plants Checklist' supports as it has no actual case studies just a French study into what toxins it might contain.

It is not on the UK HTA's list of potentially harmful plants so garden centres do not need to print any warnings about it on plant labels.

Hmm well that's interesting. Gastric problems? Not good! I have a pet rabbit so I need to keep a watch on him when he explores the garden. My cat is another one that likes to chew on things. Thank You for checking everybody!

The flower clusters aren't long enough for it to be Persicaria longiseta that is in a local walled garden as an introduction. They are keeping a small amount but weed out lots of it every year.