A Holyrood health group is facing questions after it emerged that a global medical corporation had supported it financially for a number of years, the Sunday Herald can reveal.

A charity paid for refreshments at the Parliament's cross-party group (CPG) on chronic pain, but the cash had actually come from medical devices giant, Medtronic. The charity stopped providing the CPG's secretariat after senior members of the group questioned the funding arrangement.

CPGs bring politicians and external groups together, but fears have been expressed about the role of commercial companies on the groups.

In 2011, as it had done in previous years, Edinburgh-based charity Pain Concern provided the secretariat to the CPG on chronic pain, including £949 worth of food and drink for two meetings that year and one in 2012. However, following the election of new MSP conveners - including Labour's Jackie Baillie, Nationalist John Wilson and latterly Conservative Jackson Carlaw - discussion focused around the source of the funds.

Pain Concern had received a £1500 grant from Medtronic - a US-based firm that makes products to alleviate physical distress - to fund the meeting refreshments. A Holyrood source said this method of funding triggered a debate within the group.

At the May 2012 annual general meeting of the CPG, a new secretary was elected and Pain Concern was thanked for its services.

Speaking to this newspaper, charity chairwoman Heather Wallace said the Medtronic cash had been a long-term arrangement.

She said the charity had given the catering bills to Medtronic to pay in the years before 2011, but then that year the firm gave Pain Concern a grant directly for the same purpose.

Wallace said: "They [Medtronic] held the funds aside for the year for that purpose until their policy changed and they required us to hold the funds."

She said the original way of funding the CPG was acknowledged in its minutes, but that the group's new MSP conveners "weren't party" to the revised way of paying initially. She said there had been a "breakdown of communication" between the secretariat and the new conveners.

Wallace added Pain Concern had not spent the full £1500 and handed the remainder back to Medtronic.

The grant is declared in the CPG's annual return.

Businesswoman Jacquie Forde replaced Pain Concern as group secretary in 2012. As reported by this newspaper, the Parliament's Standards Committee has been asked to look into two CPGs administered by Forde.

David Miller, a Bath University professor who campaigns for transparency in the public affairs sector, said group members had been right to seek clarity on the Medtronic funding.

He added: "This raises questions about how the Parliament is regulated. Will the CPG publish a complete list of all the financial help provided by Medtronic?"

Wilson said: "There was agreement by the co-conveners that the funding arrangements were not in the best interests of the group and the link with Medtronic through Pain Concern was terminated at the same time the new secretariat was elected."

Carlaw said: "I believe members of the CPG were grateful [to Medtronic] for their support although as co-conveners we felt that any financial support should be fully transparent."