Annual bonus - are they taxable?

I have just got my first bonus and small pay rise at my new company, upon getting my payslip I can see Ive lost more than half my bonus in taxes. Are one off bonuses taxable? Do you get the money back as a tax rebate? If so, how and when?

Hi,

Yes, the bonus is taxable. Once you return to your standard salary any refund due would come back over the remainer of the tax year. 

Thank you.