Among the issues you need to consider is the assignment of the practice contract to you by the primary care organisation holding it. Which type of contract this is - PMS or GMS - may well make a difference to whether this is possible.
There are 'due-diligence' issues relating to the business you will be taking on and any attached liabilities - particularly relating to staff who will become your employees under the Transfer of Undertakings (Protection of Employment) Regulations.
You and the GP you will take the offer from will need to have a business transfer agreement or, if a period of partnership will precede the GP's departure, a partnership agreement.
You should get some professional advice about your ongoing occupation of the surgery premises. Will you have the opportunity to buy them? Or will you will be granted a lease?
It is important too to ask a specialist medical accountant for advice.