The Herald has found itself embroiled in something of a controversy over an article we published last month.

It was by Dr Elliot Bulmer, an expert on constitutional issues. We were offered the article by the pro-indepedence Yes Scotland campaign and, having considered it carefully, decided to publish the piece as an important contribution to the referendum debate.

We accepted the article in good faith from Dr Bulmer as research director of the respected Constitutional Commission charity. We learned last week Dr Bulmer had been paid £100 by Yes Scotland for the 1200-word article.

It is The Herald's policy not to pay for such articles and we adhered to our policy on this occasion.

Details of the payment emerged from allegedly hacked private Yes Scotland emails. The organisation has contacted the police and the complaint is the subject of a criminal investigation.
However the payment the emails allude to has led to Scottish Labour calling on Yes Scotland chief executive Blair Jenkins to resign, claiming he is "guilty of deep dishonesty and deception". Better Together, the pro-UK campaign, demanded an inquiry by the charity regulator, claiming the payment was in breach of referendum rules.

Mr Jenkins insisted the payment was "perfectly legitimate", and accused Scottish Labour and Better Together, the pro-UK campaign, of displaying "manufactured outrage".

Yes Scotland is a broad church, promoting viewpoints from an array of campaigning groups, such as Business for Scotland or Labour for Independence, which are not strictly affiliated to it. That is well understood and it's why there was nothing untoward in Yes Scotland offering an article not of its own authorship.

However, Yes Scotland's opponents claim the payment shows the organisation has crossed a line and somehow deceived the public.

Has the modest fee blurred the picture? In light of this episode does Yes Scotland need to be more transparent about its relationships with unaffiliated but sympathetic groups and individuals?  
For our part The Herald undertakes to show clearly when an article has been offered by any political campaign group. We trust other newspapers and broadcasters will do the same. The media is regularly contacted by campaign groups offering opinion pieces and that trend will intensify as polling day on the referendum approaches.

It is essential the independence referendum is conducted openly, honestly and fairly. Views should be aired freely and frankly if voters are to come to a considered opinion by September 18 next year. For that to happen all campaign groups must be beyond reproach in how they conduct their business.

Trust must be earned and it's vital it is not undermined or squandered by needless distractions from the real issues. The row over Yes Scotland's modest payment to Dr Bulmer is an unfortunate but timely reminder of that.