The GMS and PMS contracts define core hours for General Practice as

8am to 6:30pm
Monday to Friday
(excluding Bank Holidays.)

It is for the practice in discussion with its patients and patient participation group to determine how services are delivered between these hours.  The core contract does not require a contractor to be on-site at all times, open at all times, or deliver all services at all times. The opening hours need to be sufficient to “meet the reasonable needs of its patients”.

8.1.1.  Subject to clause 8.1.8, the Contractor must provide the services described in Part 8 (namely essential services) at such times, within core hours, as are appropriate to meet the reasonable needs of its patients, and to have in place arrangements for its patients to access such services throughout the core hours in case of emergency.

8.1.2. The Contractor must provide-
(a) services required for the management of the Contractor’s registered patients and temporary residents who are, or believe themselves to be-

(i)  ill with conditions from which recovery is generally expected;
(ii)  terminally ill; or
(iii)  suffering from chronic disease,
delivered in the manner determined by the practice in discussion with the patient;
(b) appropriate ongoing treatment and care to all registered patients and temporary residents taking account of their specific needs including

It is not unusual for practices to subcontract a proportion of these hours to an alternative contractor to allow the practice to close for a period of time for training.  

Contractors must notify the commissioner of their intent to subcontract.  The commissioner can only object on the grounds of demonstrable risk to patients or material financial loss to the commissioner.