Patients using a premium rate telephone number are subsidising costs at a doctor’s surgery, the Guardian can reveal.

A freedom of information disclosure shows Handsworth Medical Centre, in Handsworth Avenue, Highams Park, makes nearly £500 a month from its 0844 number.

The practice introduced the premium rate line in March 2012 to replace an outdated system, signing a five-year contract with telecoms provider NEG, now known as Surgery Line.

But the surgery says at the time it was ‘misled’ about the ‘true cost’ to patients.

It also says it is looking at ending the premium rate, but would face high settlement costs.

In the 2012/13 financial year, the practice used the £475 a month ‘subsidy’ to offset monthly phone bills averaging £1,659.

The total cost of the phone system and calls for this period were £19,908 and the income generated for that period totalled £5,495.

Practice manager Josie Camplin said the premium rate was recommended to the surgery back in 2012.

She said: "At that time a 0844 number was an approved system recommended by the Local Medical Committee of the BMA and we were led to understand that patients with a land line would pay a local rate charge as would most mobile phone users who had contracts.

"We have introduced a local number in parallel to the 0844 number as an interim measure, whilst looking at options for moving away from the 0844 number.

"We are currently investigating options to see whether we can change provider mid contract, but are aware that there will be very high settlement charges."

The surgery's local rate number is 0203 006 9216.

Ian Galpin of the nation-wide 'Fair Telecoms Campaign', said:

"The practice seems to have been misled on a number of levels about the usage of 0844 numbers and has made an extremely bad business decision long after it was advised against the use of the 0844 numbers. 

"That said, patients cannot be asked to contribute a penny more to this scheme."

A local rate number was introduced in December and is advertised in the reception, on the practice website and the NHS choices website.

A spokeswoman from Surgery Line said:

"Surgery line customers are not forced to continue to use the 0844 numbers until their long-term contracts end – it is open to them to move to a geographic number on request.

"Such customers can switch, free of charge, to numbers charged at the geographic rate.

"The business cannot comment on the individual commercial arrangements of its customers. Surgeries have a contract for the lease of their telephone system, regardless of whether they use 084 or not.

"The payment of that system lease is down to the surgery’s own commercial arrangement as with other services they contract for."

Accounts for last year have not yet been released, but Ms Camplin has said the "level of subsidy remains constant", indicating patients calls to the minimum 4p-a-minute line has generated the practice over £10,000 to date.

The five year contract is due to expire at the end of March 2017.