Anglo-Irish relations have been set back by the Irish government’s “aggressive and anti-unionist” approach in Brexit talks, the DUP has claimed.
Nigel Dodds, the DUP’s Westminster leader, warned relationships in Northern Ireland linked to devolution have also been damaged and said they will “take a long time to repair”.
Mr Dodds added his party’s approach of seeking to “stand strong for the Union” and Northern Ireland’s place within it should come as no surprise.
His remarks came in the Commons after the DUP refused to accept proposals which would have shifted Northern Ireland’s customs border to the Irish Sea.
Mr Dodds said: “It should come as no surprise that the Dublin and Irish government wishes to advance its interests.
“The way it has gone about it in such an aggressive and anti-unionist way is disgraceful and has set back Anglo-Irish relations and damaged the relationships built up within Northern Ireland in terms of the devolution settlement – and that is going to take a long time to repair.
“Secondly, it should come as no surprise that the Democratic Unionist Party stands strong for the Union, stands strong for Northern Ireland’s place within the Union under the terms of the devolved settlement, and we will not allow any settlement to be agreed that causes the divergence politically or economically of Northern Ireland from the rest of the United Kingdom.
“Because to do so would not only be politically damaging but would be economically catastrophic for everyone in Northern Ireland – unionist, nationalist, Remainer or Brexiteer.
“The reality is that one of the good things that came out of yesterday is that from all sides of this House – Labour, Conservative, backbenchers, Ruth Davidson, Carwyn Jones, everybody – there is now an agreement that the United Kingdom stands together and nothing will happen that will cause the break-up of this great United Kingdom.”
Brexit Secretary David Davis replied: “He’s dead right. There’s no surprise the Democratic Unionist Party stands for the United Kingdom – so does the Conservative and Unionist Party equally.”
The DUP’s Ian Paisley (North Antrim) said: “Can I thank the Secretary of State for proving yesterday that he can listen, and that when he tells Europe ‘no’, he means ‘no’ – and we thank him on behalf of the people of Northern Ireland for that matter.”
He also asked Mr Davis to speak to the Dublin government and “let them know that if they continue down this reckless path they will end up stumping up a further £1.5 billion in membership fees to the European Union if they do not get a trade deal with us”.
Mr Davis replied: “He’s absolutely right – the best outcome for Ireland is a free trade deal and a customs agreement.”
Independent MP Lady Hermon (North Down) said DUP MPs do not represent all of those in Northern Ireland, as she asked Mr Davis to explain the “benefits of the proposals for the whole country which the Prime Minister was taking to Brussels yesterday”.
Lady Hermon, who said she was “profoundly embarrassed” on Theresa May’s behalf, told MPs: “While I readily accept that there are 10 members of the DUP in this House, duly elected, the DUP nevertheless do not speak for all of the people of Northern Ireland and do not represent all the people of Northern Ireland.”
Mr Davis said the aim for the whole country was to “maximise the trade benefits of being outside the customs union and single market whilst at the same time maintaining as much as possible of the benefits that we currently enjoy”.