AN SNP parliamentarian broke Westminster rules regarding registration of his financial interests but his mishap was a "genuine mistake", a standards watchdog has ruled.

Phil Boswell, MP for Coatbridge, Chryston and Bellshill, failed to declare a shareholding in Boswell and Johnson Limited, as he was required to, a ruling by the Parliamentary Commissioner for Standards states.

He wrongly believed that as the company had not traded since 2011, he was not obliged to declare it on his register of interests but has now apologised for misinterpreting the rules.

The findings state that the complaint was upheld but add: "I accept that this was a genuine mistake and not an attempt to conceal his financial interest... I consider Mr Boswell has made an acceptable response and that the rectification action is sufficient in bringing the matter to a close."

In a short statement Boswell said he "apologised unreservedly for misinterpreting the guidance". He added: "The company ceased trading in 2011. I did not believe that it would be reasonable for an individual to consider this would influence my actions or words, and as such I was compliant with Code of Conduct as it relates to the registration of my Directorship of Boswell and Johnson ltd."

He has now entered the directorship on his register of interests.

In a letter to the Commissioner, which was released with the findings, Mr Boswell said that he was the victim of a “concerted media campaign” which had led to his children being bullied at school and his car being vandalised.

He alleged that a Liberal Democrat Holyrood candidate, Paul McGarry, who made the complaint against him was working with a newspaper in a bid to discredit him.

Mr Boswell said: "I have never met the complainant Mr McGarry in person, and I am of the opinion that Mr McGarry is likely to be acting in concert with a particular media organisation."

The MP, who is at the centre of an internal SNP civil war in Lanarkshire, is subject to another ongoing investigation by the The Independent Parliamentary Standards Authority. It is understood to focus on promotional videos which Mr Boswell made and claimed expenses for.