Tax liability when a child is using my ebay account

My son (16 years old) has been using my ebay account (which I no longer use) to buy and sell clothing. He purchases items on ebay and from other sources using his bank account and then sells them on ebay. I transfer any sales proceeds from ebay back to his bank account without keeping anything. He has made approx. £8k profit in the last 12 months. Should he sign up for self assessment and declare this as he is expecting to earn more profit next year. Thanks

Hi,
As your son is buying goods for resale, with the intention of selling them for a profit, then it is likely that this will be classsed as trading.
If his total income from trading is over the Trading and Miscellaneous Income Allowance of £1000 there will be tax due on the profits.
Please see the guidance here:  Selling online and paying taxes - information sheet
Thank you.