What is this beautiful tree called?

I think it's an Albizzia Julibrissin. If it is then they are now grown successfully here in Essex!

I agree it looks like an albizia. A. julibrissin should grow in milder parts of the UK and eventually reach twenty feet

Common names - Mimosa tree or Silk tree

They also grow in the Southern United States. I remember their incredibly sweet scent as a child.

What the British call Bucks Fizz we call a Mimosa...orange juice and champagne.

I wonder whether they can grow in the UK.

I have one in my garden (Devon) and it is growing well - about 8 ft but no flowers yet - roll on spring!

Hi, it is certainly Albizia julibrissin or Silk tree, it flowers during the summer time. With pruning, the crown can have beautiful umbrella form. It is very nice specimen deciduous tree.