SCOTLAND'S leading secularist organisation and Catholic bishops have united to condemn a prominent Labour figure for seeking to inject religious bigotry into national politics.

Scott Nicholson, a parliamentary candidate at the 2016 Holyrood elections and until last week a member of its national executive, said an SNP MP's display of her faith at Westminster was an attempt to stir sectarianism, sparking criticisms he had displayed a "frightening level of intolerance".

In a social media post, Mr Nicholson linked an image of Glasgow MP Carol Monaghan wearing ashes on her forehead with religious bigotry.

Ash Wednesday is the first day of Lent and many Christians attend a church service at which their foreheads are marked with ash in the shape of a cross.

Mr Nicholson, a senior figure in the Fabian Society, said: "The SNP's actions aim to foster grievance with UK but I believe there are members who plan to promote sectarianism."

He later deleted the tweet and said he apologised "for any offence that may have been caused by my previous tweet regarding the SNP".

But Ms Monaghan, who represents Glasgow North West, said: "This is not an apology. This was a personal attack on me and in doing this man has sought to politicise my faith for his agendas. Ashes are not a political symbol and this has absolutely nothing to do with the SNP.

"I went to Mass as I do every year and got my ashes as I do every year. I was not making any point or any attempt to get a reaction. The overwhelming reaction I have had though has been wholly positive and from people of all faiths and none. To attempt to make a political point and accusations of sectarianism is really desperate stuff."

Ms Monaghan had been the subject of an article on the BBC about public displays of faith after she attended a Westminster committee shortly after receiving her ashes. Although associated with Catholicism, other Christian faiths, including Anglicanism, also follow the tradition.

Mr Nicholson was until last week a member of Labour's Scottish Executive Committee and stood for the party in Perthshire South and Kinross-shire. As well as a member of the Campaign for Socialism he is chair of the Fabian Society in Glasgow.

But his comments have sparked fury amongst party colleagues, with one nationally prominent member stating: "I'm really taken aback by this. "Why would you have a problem with someone having been to Mass on Ash Wednesday? This is pretty distasteful."

A spokesman for the Bishops’ Conference of Scotland said: “To suggest that a Catholic MP wearing ashes on her forehead on Ash Wednesday is an act of sectarianism displays a profound ignorance of Christian tradition and a frightening level of intolerance. Presumably, Theresa May’s decision to host a reception for Christian leaders at 10 Downing Street 24 hours earlier when she talked about her planned Lenten sacrifices was also an act of sectarianism?”

A Scottish Secular Society spokesman said: "There is no problem with people making displays of their faith at work or on particular days. It is not a call for sectarianism, attempts to create splits or create a dark shadow or religious bigotry. This is about someone attempting to tie a political party to religious divisions and that cannot be welcomed."

Labour MSP Elaine Smith said her party colleague's comments breached equalities expectations, adding: "Mr Nicholson should apologise and reflect on what is a deeply offensive comment about Catholics who have been witness to their faith."

A Scottish Labour spokesman: “Scott Nicholson has apologised for the offence he has caused with his inappropriate comment.

“Scottish Labour is very clear that all members have a responsibility to conduct themselves respectfully at all times.

“This generation can be the one that stamps out sectarianism for good, and Scottish Labour firmly supports a renewed push towards tackling sectarianism in classrooms and the communities."