Just under a week since Nick Griffin caused controversy by tweeting the private address of a gay couple who won a legal battle against the owner of a bed and breakfast for refusing to allow them to stay, he has been formally reported to the European Parliament.

Labour MEPs have lodged a formal complaint against Mr Griffin for the tweet, and the British National Party, of which he is leader, may face sanctions under the rules of the European Parliament.

Glenis Willmott, leader of Labour MEPs, said tweeting their private address to Griffin’s “thuggish BNP supporters is an appalling example of homophobic incitement to violence.

“Inciting violence or even implying an invitation to mob justice is unacceptable from anyone, all the more so an MEP,” she said.

Michael Cashman MEP, who represents Labour on LGBT issues added: “I brought this to the attention of the President of the European Parliament, who should act swiftly and officially”.

He added: “Under European Parliament rules, MEPs’ conduct ‘shall be characterised by mutual respect, and be based on the values and principles laid down’ in EU treaties, including respect for minorities’ dignity. Nick Griffin certainly failed those values when he incited his followers to give a gay couple ‘a bit of drama’”.

As well as facing possible sanctions from the European Parliament, an Irish ”underground” news site called Rabble has reportedly posted the address of BNP leader Nick Griffin on its Facebook page.

The photograph shows a stamped envelope with Mr Griffin’s title as an MEP and a full address, and was published on 19 October and has received over 10,000 shares.

Dyfed-Powys Police have been carrying out an investigation into Mr Griffin’s online behaviour along with their counterparts in Cambridgeshire – the county where John Morgan and Michael Black reside.

Last week, Mr Griffin called the couple “2 bullying ‘gay’ activists” and tweeted their address with the remarks that a “British Justice team” would be coming to “give you a… bit of a drama”.

It was after their legal victory against the Christian owner of a bed and breakfast who refused to let them stay in a double room because of her religious views.

Despite Mr Griffin’s actions, the couple said at the weekend that they were not willing to press charges against the BNP leader and have described his behaviour as amounting to “hot air”.

Mr Cashman concluded by saying: “I do hope the parliament will take serious action. This is a sad reminder of the homophobia and violence LGBT people still face.”