A number of NGH volunteers are considering resigning as a result of an 'unwarranted' parking charge at the hospital.
John Patterson, 69, volunteers for four hours a week with the Friends of Northampton General Hospital, a service who man the three reception desks and have assisted outpatients and visitors for 20 years.
But now he claims that due to a shortage of parking, the Friends of Northampton General Hospital have now been asked to pay for spaces in order to carry out their not-for-profit work, amounting to about £5 per person, per shift.
He said: "The reception and buggy service receive very positive feedback from our clients, the outpatients and visitors.
"This totally unjustified and high-handed action by the management of NGH threatens the future of the service. I know a number of volunteers who are considering resigning as a result of this unwarranted charge. This could cause the service to collapse.
"I feel strongly about this. I enjoy my volunteering and believe I am giving something back - the economic and moral basis for this action by NGH is indefensible."
The friends also provide a buggy service to take those with disabilities or who struggle with mobility clinics.
Until recently, the friends worked with a further 120 volunteers who were ward or clinic based, who performed filing, feeding or general non-medical services.
Now the 120 charity workers have been transferred from their independent organisation and are organised by an NGH voluntary services manager. They do have the choice to reclaim parking expenses within a maximum daily limit but still need to find the money in the first instance.
John claims that if the Friends of NGH charity reimbursed the workers parking charges it would cost the charity around £15,000 per annum.
He added: "We occupy around six parking spaces per day, for the 12 part-time volunteers - each day there are two shifts of six volunteers covering four hours each shift - we are 80 in total.
"We estimate that using minimum wage calculations and applying NI we save the hospital around £125,000 per year in full-time equivalent salaries. This figure makes no allowance for pensions, sickness or holidays as we operate relief cover from the volunteer pool.
"I think for a lot of people this will be the final straw."
Throughout 20 years of service, the charity has fundraised for two patient buggies and have recently donated sums of £19,000 and £25,000, raised from raffles and car boot sales to provide items towards clinics, which cannot be funded through NGH or the NHS, workers say.
A spokeswoman for Northampton General Hospital said: “We have to balance the needs of everyone who comes here, whether it’s to work, to receive treatment or to give their time voluntarily to support us.
"Continuing to provide volunteers with free parking is simply not sustainable given we that don’t have enough parking spaces to meet demand.
"We would encourage the Friends of NGH to consider supporting their volunteers by reimbursing their travel costs, as we do with our in-house volunteers.”