A prominent Scottish public affairs specialist has broken ranks with his industry by calling for a statutory register of lobbyists to be introduced.

Mark Cummings, the founder and owner of Invicta, said his and other firms should have to obtain a "licence to practise" before they can represent their clients to government. He believes this would clean up the industry.

He argued a law would help weed out lobbyists who were "totally unaccountable" and "not suitable" for the job.

The call comes as Labour MSP Neil Findlay prepares a bill to regulate lobbying at Holyrood.

He is proposing a register of practitioners that would compel lobbyists to declare their clients and fees.

Meetings with MSPs, ministers and councillors would also have to be registered.

Findlay's definition of "lobbyist", upon which he has consulted, includes standalone firms and in-house specialists as well as charities and trades unions.

However, parts of the lobbying industry have come out strongly against the plan, instead preferring the status quo of voluntary self-regulation.

The Scottish Council for Voluntary Organisations, which represents hundreds of charities, described the proposal as immoral, while the Association for Scottish Public Affairs said it was not convinced the plan would improve ethics or transparency.

In an interview with the Sunday Herald, Cummings, who set up his Edinburgh-based business in 2007, said he favoured a register for public affairs companies and in-house specialists. He said: "I don't think industry self- regulation for public affairs is ever going to pass the credibility test for observers. I don't think people are going to buy it.

"I support the idea of having a statutory underpinning to a register. I think it's a good idea that if you want to operate as a public affairs professional, either in-house or in an advisory capacity, then there is a register of people doing that work."

Cummings said only those firms or individuals that sign up to the ethical standards required to be added to the register should be allowed to lobby politicians.

He said he was effectively calling for the introduction of a "licence to practise", adding: "If you are going to regulate the public affairs industry, it should be from the point of view of protecting the clients. They are entitled to a good-quality service, delivered ethically."

Cummings, whose clients have included property developers, supermarkets and energy companies, said a register would also promote good practice in the sector.

"This is an industry that people think they can have a go at. People walk up and think, 'I can do this'. That's where the quality and the standards drop. You get people who are not suitable for this," he said.

Cummings said he had concerns about "the one-man or one-woman bands, spinning in and out of different roles in life, trading on their contacts, who are totally unaccountable".

He added: "I have seen limited examples of people operating in a way that I wouldn't want to operate, and I find that concerning for the industry."

However, he disagrees with Findlay's proposal in a number of areas. Cummings is sceptical of the requirement to disclose fees and clients, and does not believe publishing details of meetings would be helpful.

He added: "Neil has started a debate, but I think his proposal is too narrow in how it is drawn."

Cummings also said his preference was for a UK-wide scheme and that he wanted the language of the debate to change. "I hate the term 'lobbyist'," he said. "For a start, nobody really understands what it means. You don't ever get a job which has the word 'lobbyist' in it. Lobbying is an activity, but in itself it's not a profession."

Findlay is planning to publish a summary of his consultation responses early next year, followed by a bill.

Stuart Crawford, who runs his own public affairs consultancy, said: "A 'licence to practise' would essentially encourage privileged access, something the Scottish Parliament was set up to expressly discourage. Anyone within the lobbying sector advocating such an idea needs a cold bath and an Alka-Seltzer to avoid coming out with any more such nonsense."

Findlay said yesterday: "I welcome this intervention by Mark Cummings. It is becoming ever more clear that there are a range of differing views within the public affairs and lobbying sector.

"I hope that responsible, professional organisations and lobbying firms will engage positively so that we ensure that we create a system that works for everyone. This has been my intention all along. No-one should fear transparency and scrutiny."