Hello and thanks for using Just Answer.
I am Al and am happy to assist you with your enquiry.
If you purchase a business as a going concern, which you will be, you are under a duty to retain all existing staff, and if you were to sack them, they would have a case for unfair dismissal against you.
I hope this assists you and sets out the legal position.
What if the previous owner closes his business and we re-open the shop as a transfer of our business to the new shop.
If the current owner closes his business and you then take over in the premises and trade under a different name, you would not need to retain any of the staff employed by the current owner.
Hope this helps.