Cap gains

I've made about 6k in my IB account this tax year. Will I need to pay tax on that if it stays in the account, or do I just pay the cap gains when I withdraw the money from my account?

I have more than 10k cap gains from my other trading this year, so I will not fall below the allowance.

I believe you will have to pay CGT on the gain in that account as you have actually earned the income despite whether you have withdrawn it or not. The account is in your name therefore you are liable to pay the tax.

Although I may be wrong!

Cheers,