A chiropractor with a string of letters after his name has been warned not to call himself doctor while touting for patients.

Known as Bob by friends and patients, Robert Mackay DC, MA, BSc, LLB, BA (Psy), BA (Phil), Dip HSW, Adv Dip Crim, Adv Dip Child Dev, Cert Health Prom, Cert Ed, LCSP (Phys), (ex MMCA), lives and practices in Marston Road, Marston, Oxford, and has 30 years worth of evening class and Open University education.

But the Advertising Standards Authority (ASA) said the title "Dr" on leaflets and letterheads promoting his services could imply he has a general medical qualification.

Mr Mackay, 56, said chiropractors, who manipulate the spine to treat a range of illnesses, had been allowed to take the title for 40 years.

He said: "I hardly ever say I'm a doctor except on leaflets which I have published. As long as I make it clear that I'm not a GP I have been told I can carry on using the title."

The ASA challenged Mr Mackay after Oxford County Council trading standards officers questioned whether his qualifications were genuine and, if they were, whether he should be allowed to list those unrelated to his profession.

Mr Mackay, who is currently studying for a History MA, produced all his certificates for the ASA and explained he wanted potential patients to get a "general picture of himself". The authority did not object to this.

He said: "The trading standards officers could have asked me for my certificates - I would have been happy to show them. I don't really know why they went to the ASA, although I'm not angry because I try not to get upset with anyone if I can help it.

"I love to be studying something and keeping myself busy. It's not only education - I also play the piano and do martial arts."

A spokesman for the General Chiropractic Council said many chiropractors used "Dr" as a courtesy title.

She said: "The Medical Act 1983 lists titles which are restricted for use by registered medical doctors only. Dr' is not amongst them and it is only illegal to pretend to have a general medical qualification.

"Medical doctors do not usually have higher degrees or PhDs themselves, and so "Dr" is just a courtesy title for them, too. Provided that a chiropractor's adverts are quite clear about their status and experience, they have not committed a criminal offence if they refer to themselves as "Dr"."

Oxfordshire principal trading standards officer Martin Allen said: "We were worried about the number of qualifications Mr Mackay had - something we come across a lot. Some people claim to have as many as 50 or 60.

"We wanted to know whether he was misleading the public and just added letters after his name when he felt like it. We were happy after we knew they were all genuine. It was the ASA which decided he should not use the title Dr."

Mr Mackay's qualifications, and when he received them:

DC - Diploma of Chiropractice (1990), MA - Master of Arts (1994), BSc - Bachelor of Science (1985), LLB - Bachelor of Law (1980), BA (Psy) - Bachelor of Arts (Psychology) (1975), BA (Phil) - Bachelor of Arts (Philosophy) (1981), Dip HSW - Diploma Health and Social Welfare (1983), Adv Dip Crim - Advanced Diploma Criminology (1997), Adv Dip Child Dev - Advanced Diploma Child Development (1998), Cert Health Prom - Certificate in Health Promotion (1996), Cert Ed - Certificate of Education (1971), LCSP (Phys) - London and Counties Society of Physiologists (Physiology) (1995), Ex MMCA - ex member McTimoney Chiropracticc Association (1991) Mr Mackay left this organisation so he did not have to join the general chiropractic register - a society which supports its members.