Brexit could irrevocably reorder UK, says Peter Mandelson

Britain's departure from the EU could "irrevocably reorder" the United Kingdom through the restoration of a hard border between the two parts of Ireland, former British minister and EU commissioner Peter Mandelson will warn on Tuesday.

Mr Mandelson, who was Northern Ireland secretary from 1999 to 2001, will use a speech to British and Irish business figures in London to highlight the risks posed to Ireland by Brexit.

He will tell the British Irish Chamber of Commerce that the potential impact on Northern Ireland “and by extension, the Republic of Ireland” goes beyond economics and concerns the future balance of the UK.

"Alongside the very real threat of Scotland's departure through a second referendum, the possible re-emergence of a hard Irish border between North and South means a vote to leave could irrevocably reorder our United Kingdom. Just like the future of our economy, those campaigning for the UK to leave Europe are unable to tell us how the component constituencies of the UK would co-exist outside the EU," he will say.

“Our cultural, economic and familial ties would of course not be severed, but they would be impacted. This not only underlines the seismic nature of this decision, but the scale of the risk if we leap the wrong way.”

Peace process

Describing the EU as “a fundamentally stabilising presence in Ireland’s recent history” as well as an enabler of the peace process in Northern Ireland, Mr Mandelson will argue that Britain and Ireland’s shared EU membership is an important part of the framework supporting peace. He will accuse pro-Brexit campaigners who speak passionately about the need to “take back control of our borders” of avoiding any discussion of the implications for the UK’s only land border.

“It is unclear what the border arrangements would be in the unprecedented situation of the UK leaving Europe – and everyone would want to work to avoid border posts and elaborate checks – but the re-imposition of a formalised border would be a radical departure from the established strategy of administrations in Dublin, Belfast and London,” he will say.

“Anything, in my view, that strengthened a sense of separation between northern and southern Ireland – physically, economically, psychologically – has the potential to upset the progress that has been made and serve as a potential source of renewed sectarianism.”

Trade deal

Mr Mandelson will also use the speech to pour scorn on London mayor Boris Johnson's suggestion that Britain should negotiate a trade deal with the EU similar to that currently being negotiated between the EU and Canada. Mr Johnson on Monday set his sights on US president Barack Obama, who is expected to call for Britain to remain in the EU when he visits London next month.

Writing in the Daily Telegraph, Mr Johnson said such an exhortation would amount to "outrageous and exorbitant hypocrisy" from the leader of a nation which so jealously guards its sovereignty.

In the House of Commons, the government rejected a call from Labour for an investigation into whether justice secretary Michael Gove breached his oath of confidentiality as a privy counsellor by revealing Queen Elizabeth's private hostility to the EU. Mr Gove has been widely fingered as the source for a report in the Sun last week that the queen had vented her anti-EU feelings during a lunch at Windsor Castle five years ago.