Capital gain tax and capital allowance

I know that the assets can use the capital allowance with written down allowance. If a business car is bought at 10000, if I apply the allowance in the first year 18% and there is 8200 remain in the main pool. And in the profit and loss account suppose I have written it is depreciated by 1000, it will remain 9000 in the balance sheet. If I then sold it at 8500, what will it affect my capital allowance and the capital gain tax?

Hi Chun Ho Chan,
Please refer to Capital allowances when you sell an asset
Thank you.