The MS Society has apologised after a tweet promoting a fundraising fun run accidentally appeared to endorse one side of Northern Ireland’s bitter sectarian divide.

Last week, the charity tweeted to its 53,000 followers an advertisement for a fundraising walk it has planned to hold in Belfast this September.

“Let’s turn the streets of Belfast orange!”, it said, in a reference to the MS Society’s brand colour, with a picture of supporters wearing bright orange t-shirts.

However, orange is also the colour of the Orange Order, a hardline unionist association which famously holds marches across Northern Ireland each year.

Orange has been associated with Protestantism and unionism in Northern Ireland for centuries in honour of William of Orange – the Protestant Dutch king whose armies defeated the Catholic James II in the late 17th century.

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Marches by the Orange Order were often flashpoints for sectarian tension during the Troubles.

To this day, marching by the group is regulated by the government’s Parades Commission to ensure they do not provoke breaches of the peace or inflame local anger.

The tweet was deleted shortly after it began provoking comment on Twitter, but not before hundreds of users poked fun at the faux pas.

“I know Norn Iron history isn’t really taught much in schools over here but you surely would pick up enough from the papers to realise that 'Let’s turn the streets of Belfast orange' wasn’t really the way to go,” wrote one user, SueB, online.

Ian Wiggins added: “Looks like we’ve got a new top tweet for ‘has anyone from the actual place we’re talking about seen this?,” ending his tweet with the facepalming emoji.

The MS Society tweet which provoked amusement online

In a statement, a spokesperson for the MS Society — which campaigns on behalf of those with the nerve-damaging condition multiple sclerosis — apologised for the tweet, describing it as an “honest mistake”.

“We’re sorry for any offence caused by this tweet and understand how it may have been interpreted.

“Orange is the MS Society’s brand colour, and this campaign was used to promote our MS fundraiser across the whole of the UK.