It is Sparganium erectum or Branched Bur-reed.

it is a native plant. its lovely.

if it sets seed I'd like to be cheeky and ask you to send me some if you could. :o)

was wondering did the Mitella do anything for you or did it die off? if it did I can send you more back end of the year.

That was my next question SBG - it's growing around a public pond not mine.
I don't mind going back for seed - was thinking along those lines. I've done a google search so now know what the seed heads look like. So yes, I'll send you some. It was rather late in the day to spend much time feeding the swans and ducks so I'm sure my nieces won't mind another visit :)
The Mitella has taken. I managed to get 3 plants going -they are still quite small but I suspect it was because the soil wasn't quite warm enough when I transplanted them out into the garden. A big thank you x

good, perfect excuse for another trip to the ducks :o)
yes please and glad the mitella has taken. Mine have just been in flower 3-4" flower spike of green flowers not dis-similar to a mini heuchera flower