A leading doctor who chaired an NHS body that drew up clinical guidelines for heart conditions has financial links to companies which market drugs for coronary problems.

Professor David Newby withdrew from some of the discussions at the high-powered group due to a “potential conflict of interest”.

However, the value of most of his payments has not been made public, fuelling the debate on the relationship between Big Pharma and doctors.

Dr Peter Gordon, an NHS consultant for over 20 years who campaigns for transparency, said: "This clinical guideline has the potential for mass prescribing, so it is crucial we know how much a chairperson has been paid by industry."

In primary care alone, around £1billion of the total NHS budget in Scotland is spent on medicines and treatments by drug firms.

This financial interest has led to moves to shine a light on industry payments to health professionals.

The Association of British Pharmaceutical Industry (ABPI) recently unveiled a database of fees and support for doctors and other staff, but the recipients are only named if they consent.

As revealed by the Sunday Herald, Big Pharma supported doctors, nurses, pharmacists and health bodies in Scotland to the tune of around £4.5million in 2015.

However, attention has now turned to doctors who draw up the national clinical guidelines for NHS quango Healthcare Improvement Scotland.

The public body assembles experts to produce so-called ‘SIGN’ advice to promote clinical good practice.

In the last two years, SIGN reports have been produced on issues including epilepsy, asthma and the management of lung cancer.

The most recent document concerned “acute coronary syndrome”, or ACS, an umbrella term for situations where the blood supply to the heart is blocked.

The SIGN guideline in this area is crucial: coronary heart disease is the single biggest cause of death in Scotland and the rest of the UK.

In Scotland in 2012, heart disease accounted for 16% of all deaths in men and 11% for women.

Newby, the chair of the SIGN group for ACS, is considered an expert in the field. He is a cardiology consultant and NHS Lothian’s director of research and development.

According to the register of interest he submitted last year as part of his SIGN work, he declared “specific” financial links to some of the world’s biggest pharmaceutical companies.

The registered support was for “attending conferences, consultancy fees, grants, clinical trials [and] research projects”.

Of the near 20 pharma companies mentioned in his register, a significant number are behind treatments relating to ACS.

One of the firms is Amgen UK, whose injectable Repatha product is for patients at high risk of cardiovascular incidents.

In June, Repatha was not recommended for use by the Scottish Medicines Consortium, which advises the NHS on new treatments.

Another financial link is with AstraZeneca, which is responsible for Ticagrelor and Plendil, the latter of which is used to treat high blood pressure and angina.

Boehringer Ingelheim, a pharma firm based in Germany that was also on Professor Newby’s list, is responsible for Pradaxa, which helps prevent blood clots.

Bristol-Myers Squibb, in partnership with Sanofi Aventis, markets a tablet-based treatment for ACS called Clopidogrel. Both companies appeared on his register of interest.

So too was Eli Lilly and Co, which is linked to the Prasugrel tablets that helps guard against blood clotting.

Similarly, Novartis Pharmaceuticals, which recently got the green light by the SMC for its heart pill Entresto, has had a financial relationship with Newby.

Pfizer, which manufactures cholesterol-reducing statin Lipitor, was also named on the professor’s transparency document.

A spokesman for HIS said of Professor Newby’s role on the group: “In relation to the SIGN guideline on acute coronary syndrome, Professor Newby was not present during discussions where it was considered there was a potential conflict of interest and he took no part in developing those recommendations.

“Following discussion and agreement, Professor Newby delegated authority to the Chair of SIGN, Professor John Kinsella, who oversaw the final guideline group meeting where the recommendations were approved.”

There is no suggestion of any wrongdoing by the doctor, but the links raise fresh questions about the breadth of information required to be registered by medics.

Three other members of the SIGN group declared financial links to either drug or medical companies, but the value of the support is not provided.

However, Professor Newby was one of the doctors to consent to details of payments received by Big Pharma being published on the separate ABPI database.

He benefited from £9,249 worth of support from AstraZeneca, including £6,000 in “fees”, £1,250 in registration fees and £1,946 that covered “travel and accommodation”.

Gordon said: "I've been concerned about SIGN's governance of conflicts of interest for several years. The governance of the SIGN guidelines is not as good as it is in England. The principle difference is that the scale of payments aren't given, and there are no dates for the payments."

An NHS Lothian spokesperson said: “Professor Newby declared an interest where appropriate and actively stepped aside when decisions were made to ensure the governance process could not be questioned. In addition, he requested his details were published in the ABPI database to ensure transparency.”