Help needed to identify this?

We've just moved into our new home and have two bushes in our front garden. One is absolutely covered in the pest shown in the photograph. I'm rubbish at gardening and have no idea what it is despite a fair bit of internet searching.

Any help to identify and treat the infestation would be greatly received. Both the white and black bits have spread to the neighbouring bush in our garden now so keen to sort it out. Nothing is moving at the moment but don't really want to leave it until the summer to find it covered in crawling beasties!

For size, the pests are only a few mm in size.

Thanks so much.

 

Possibly Euonymus scale. See here for more info https://www.rhs.org.uk/advice/profile?PID=798

 

Thanks both.

Nothing flies off when I give it a shake and looking at Nigel's link, it's identical to the picture. Thanks so much for the info, I'm going to get myself some appropriate chemicals and try to stop the spread to the next door (smaller) shrub. Luckily not many plants in the front garden!