Practical Commissioning's Jargon Buster explains the meaning of the term 'Commissioning'.
Commissioning means buying services that best meet the needs of the local population.
Commissioning is usually done by PCTs. But the beauty of PBC is that it allows GPs with a indicative budget to get involved and commission services for their patients making the purchase of NHS services more granular.
When GPs choose to do this the PCT is still involved as it still retains responsibility for expenditure. So in practice the PBC group will look at a existing service, discuss a better way it could be designed and suggest such a service be commissioned and submit a business plan to the PCT. The PCT's role then becomes to procure such a service from a suitable provider.
Sometimes the PCT may commission a GP PBC group to provide a service.