UK Tax bracket for 100k

[Lee1983]

The rise in my base pay from 80k to 99k puts me just below the 100k tax bracket.
I have a sales-based job and earn around £15,000 to £20,000 in commission each year.
Does my commission place me in a higher tax bracket than my base pay, or is this kept separate?

Thanks in advance

 

[vijaygandhi]

Yes, it will put you in higher rate tax bracket and also your personal allowance will get reduced by one pound for every £2 increase in your income after £100K.