Is it in the ground or in a pot? What treatment did you use to get rid of the scale, and has the scale all gone? And what part of the UK are you in?

It is in a pot, used Wilkinsons multi purpose bug killer. This worked, I picked off all the scale till none remained. I am in Liverpool. Thanks.

Okay, scrape back small areas of bark with a fingernail - start near the top and if that's green and moist underneath, then don't do any more test patches. If all the wood underneath is brown and dry, the plant has probably died. If you find any 'live' areas, if you've not repotted for a couple of years, turn out the plant and check the rootball to see if its potbound - if so, get a larger pot and new compost and repot it. Then keep well watered - and a check for scale, of which there seems to be an inordinate amount this year. Make sure the insecticide you used does not exclude Acers as unsuitable plants for the product.

Have scraped, found that one half of the tree is moist and still green but the other half is white and very dry, just looking at the dead half even the branches on the outside are white as opposed to the other half which is red. Will check the rootball and if needed will repot. Thanks for advice, glad I will at least have half a tree. This was a little stick when I bought it and was the first plant I ever had, was very proud that it had grown 3ft+.

Half a tree, lol, made me laugh - cut out anything you know is actually dead and if you want to reshape it because it looks odd, leave that till late autumn or midwinter - Acers don't like being pruned this time of year, they bleed excessively. And when I say late autumn, I mean early November really... you don't want to encourage new growth at the end of the season by doing it too early.

Thanks for advice, will cut out dead branches. Will have to prune in November as it is going to look very odd!