Please identify my plant

I think it is a yellow form of Euphorbia millii (crown of thorns) which is more often red. I had one for many years on a school windowsill-don't know if its still there.Yours looks very nice!

Thanks, Celandine, have you any tips on how to look after it. I water it when it feels dry and feed it in Spring.
Did you used to prune the long spiny spems?
Joyce