Brexit puts flow of Irish people, products and services at risk
Irish business faces disruption for workers and a rise in transport costs, if Britain votes to leave the European Union next months, an influential committee of Westminster MPs has said.
Checks for people travelling between the island of Ireland and Britain could be strengthened after Brexit, they said.
New physical barriers will slow the flow of goods potentially between both the two islands, and along the Irish border, adding to business costs.
With services an increasingly important element in cross-border trade, the easy movement of people to sell and execute those services is a major boon to trade, and would be threatened.
Screening already carried out by some airlines flying between the North and the rest of the UK would be robust and extended to passengers at ferry ports like Holyhead in Wales and Stranraer in Scotland, MPs said.
The Northern Ireland Affairs Committee said that imposing controls along the land boundary between Northern Ireland and the Republic, which is crossed by up to 30,000 commuters a day for work, would cause considerable disruption.
The committee found: "An alternative solution might be to strengthen the border between the island of Ireland and the British mainland (sic).
"There are fewer crossing points to enforce and it would be less disruptive as there are already checks in place.
A report by the Westminster committee, entitled 'Northern Ireland and the EU Referendum', said there were nearly 300 formal, and many informal, crossing points between Northern Ireland and the Republic.
A 2001 study estimated that 18,000 commuters crossed the Border on a daily basis and one witness told the inquiry the figure could be as high as 30,000.
The Northern Ireland Office has warned that arrangements guaranteeing free movement of people and goods to and from the Republic could be threatened in the event of Brexit.
Since the 1920s, the UK and Ireland have operated a common travel area, which allows nationals of both countries to travel and live in each country without immigration controls.
Both are also currently part of an EU customs union, which means that there are no controls on the movement of goods.
The committee comprises MPs who support both the Leave and Remain campaigns.
Its report also identified the potential impact of a Brexit in key areas,such as the economy and agriculture.
It said: "In the event of a vote to leave the EU, it is imperative that Northern Ireland's economic priorities, such as gaining a good deal for agricultural and manufactured goods, are given due prominence by the UK government in any subsequent negotiations.
"However, the likelihood of this cannot be guaranteed."
The Northern Ireland Secretary, Theresa Villiers, inset, is a 'Leave' campaigner. Northern Ireland Office Minister Ben Wallace said the economy would be more vulnerable if the UK left the EU.
He said: "I am not sure the unionist leaders in Northern Ireland would like the concept of internal borders in the UK.
"I would not like that as a unionist and I am not sure the DUP voters would."
He said both sides agreed that the peace process was secure, adding: "We have relative peace in Northern Ireland because of the efforts of people in Northern Ireland and that is to be applauded."
Mr Wallace questioned the need for change, asking: "People ask themselves what is it that is broken that needs fixing, that we take that risk?"