Sinn Féin has decided to campaign for the United Kingdom to remain a member of the European Union because it fears a British exit could further divide the island of Ireland.

The party’s ardchomhairle has agreed a strategy ahead of the British referendum on EU membership expected to be held late next year.

A strategy paper stresses three key objectives: to oppose the exit from the EU, to campaign to recognise the democratic vote of Northern Ireland, and to encourage greater co-operation between the North and the Republic of Ireland.

In the document, Sinn Féin outlines concerns about the effect a British exit, colloquially known as Brexit, could have on the economy in Northern Ireland and the North’s relations with the Republic.

Sinn Féin MEP Matt Carthy said: “Under normal circumstances we would allow the British people to control their own destiny. But obviously when they have control over our own island it brings an additional dimension to it in terms of the effects a Brexit would have.”

Trade relations

It will also campaign strongly for the outcome of the vote in Northern Ireland to be recognised by the British government. This would mean that if people in the North voted to remain in the EU, Sinn Féin is arguing that decision should be respected.

Mr Carthy said this would bring constitutional difficulties but this would remain Sinn Féin’s position. “Greater hurdles have been overcome,” he said.

Sinn Féin’s paper also outlines some of the potential consequences of a vote to leave the EU. It says Brexit would harden the division between north and south in Ireland, with the potential for customs checkpoints, trading tariffs and adverse knock-on effects for all-island economic activity and cooperation.

Negative impacts

The party has campaigned against Europe in previous referendums, including votes on the Lisbon treaties and the recent fiscal stability treaty.

Mr Carthy denied the decision on the forthcoming referendum was a seismic shift for the party and said it would continue to fight for a better EU.

“Our position has been very clear. We critically engage in the EU. The EU, as it stands now, is not a model we would have great affinity for. We are attempting all the time to try and bridge the democratic deficit that is there and try to underscore the unequal in terms of how European institutions work in many instances.

“The fact that, more and more, the European Union is moving away from a social Europe basis to a very much right-wing agenda – that is something we are challenging. And the concept of member states working together on issues of mutual concern has been eroded by some of the larger countries, particularly France and Germany, forcing, and in some cases bullying, smaller countries.”

He added: “We have been at the front of that as a country, as have Greece and Spain and Portugal. It is not to say we have any great affinity with the European Union as it currently stands, but we see a role for European co-operation and a European Union rather than the EU we currently have.

“We don’t see anything progressive in terms of David Cameron’s agenda, which is an attempt to undermine the aspects of the EU that have worked well in terms of workers’ rights and women’s rights and citizens’ rights.”