A doctor who wrote a damning attack on Ukip’s health policy for the Guardian’s Comment Is Free has failed to declare in the article that he is an active member of the Labour party, and was even shortlisted as a possible candidate in the Heywood and Middleton by-election due to take place next week. The article has already been widely shared on social media.

Dr Kailash Chand, a GP with the Tameside and Glossop primary care trust used his role as the deputy chair of the British Medical Association to give weight to his criticisms – but failed to mention that the BMA is a non-partisan organisation, whose 150,000 strong membership is drawn from across the political spectrum. Breitbart London has seen a letter that Dr Jon Stanley, a fellow BMA member and Ukip activist, sent to the leadership of the BMA, raising concerns that Dr Chand’s comments risk bringing the organisation into disrepute. Dr Stanley wrote “I do believe he has at best unintentionally led the public to believe the BMA has taken a formal stance of opposition to UKIP by not disclosing a clear conflict of interest.”

In the article, Dr Chand writes “Ukip… would sell off the lucrative parts of the NHS quicker than the present government given half a chance. Private firms and charities will be encouraged to bid for contracts, and the party would implement a “patient passport” policy that would allow patients to choose where they get treatment, or even take 60% of the cost of operations out of the NHS to go private.

“In addition, patients could obtain “health credit vouchers” to opt out of NHS care altogether and buy insurance policies from private companies.”

Within the last 24 hours the article has been shared widely on social media by Labour party supporters and left wing commentators as proof positive of Ukip’s intentions. Yet the Ukip manifesto is still to be finalised, let alone published.

In a statement on the Ukip website, head of policy Tim Aker said “UKIP will defend the NHS and services you rely on. Money can be saved from the quangos and we can get better value but we support and defend the policy that healthcare should be free at the point of need.”

He also attacked Labour’s record on health, saying “Labour are the party that carried on the PFI project in the NHS. In addition their open borders policies turned it into an international health service, costing £2bn per year.

“Only recently Labour’s Lord Warner announced plans to charge NHS patients £10 a month to use the NHS. Labour are only putting around lies about UKIP to hide their own agenda.”

In a hyperbolic moment, Dr Chand writes “If the NHS is on the brink of extinction now, it will surely be put in a graveyard if Ukip has its way,” and uses for evidence an old Facebook post by Ukip Deputy Leader Paul Nuttall, which read “I would argue that the very existence of the NHS stifles competition, and as competition drives quality and choice, innovation and improvements are restricted. Therefore, I believe, as long as the NHS is the ‘sacred cow’ of British politics, the longer the British people will suffer with a second-rate health service.”

Commenting on the comparison between competition and sacred cows, Dr Stanley retorted “Sacred cows are not open to criticism and those who commit to the system first cannot put the individual patient first.”

Referring to a scandal in which as many as 1200 elderly patients were found to have died of neglect and thirst in an NHS hospital, he added “It was a culture of secrets, aversion to criticism and lack of a sense of fallibility that led to the Mid Staffordshire scandal.”