I would have thought that, if it's an NHS or publicly-funded surgery, as opposed to private, then they're caught by FOI. 

You are entitled to request any information under FOI.  Just send a letter/e-mail headed Freedom of Information Act 2000, specify what you want to know, in what format, and give your name and address for response.

They have to reply within 20 working days, but they may invoke one of the exemptions under the Act to avoid providing the information.  If they do, you can challenge the decision, ultimately by going to the Information Commissioner.

Many thanks for the information. I shall be writing to my GP and I shall post a reply when I recieve it.

Regards

Section 43 of the Freedom of Information Act, provides a limited exception of “Commercial Interest”.  Commercial interest relates to an organisation’s ability to successfully participate in its commercial activity and is strictly applied.  An NHS doctor has a very limited commercial activity; if any.  It would be unlikely that the disclosure of a geographical telephone number could be resisted by using section 43 of the Act.

I agree, disclosure under the FIA is only part of the solution, but it does force organisations to think about the issue.
The real aim is to force the doctors to change to a normal geographical number; the contractual approach will probably achieve this.
A patient using a BT call box would have to pay £1.80 for a 10 minute call to the doctor; surprisingly this also applies to an 0845 number as well as an 0870 number.

I think someone bought up about the NHS being free, but we get charged for prescriptions.  I'm sure that was bought up in the other thread.

However, we don't have to give our GP that prescription money.  It can go to the pharmacy although some GP's offer an in house prescription service as well.

However if you're stuck at home, and need a doctor on call, it is urgent that you call the surgery, rather than walk and make an appointment, therefore you MUST use the phone.

Other commercial activities in surgeries might be profit sharing on vending machines, selling of healthcare products, and prescriptions, however patients do have a choice whether to use these services, and some patients might find the convenience of being able to buy a coffee from the vending machine, or picking up their prescription at the surgery useful.

However, those that use 0870 don't give patients a choice (unless they're forced to)  Nobody finds using an 0870 number cheaper than calling a geographical number, and there's no benifit to the patient.

It doesn't make answering the phone any easier, because you still speak to the same receptionist.  I don't class being put on queue as a benefit, because you're paying NEG to wait for your call to be answered.  With an engaged tone, you just redial until you get through.