LONDON (Reuters) - Brexit-supporting rebels in British Prime Minister Theresa May’s party set out proposals on Wednesday which they said would allow trade to flow over the Irish border while safeguarding the integrity of the European Union’s Single Market.

An anti-Brexit demonstrator waves flags outside the Houses of Parliament, in London, Britain, September 10, 2018. REUTERS/Hannah McKay

The issue of preventing a hard border between the United Kingdom’s Northern Ireland and EU-member the Irish Republic is one of the main outstanding sticking points in negotiations between London and Brussels ahead of the British withdrawal on March 29.

Both sides want to avoid such a hard border because it could undermine a 1998 peace agreement that ended decades of sectarian conflict in the north, but it is still unclear how goods crossing the border in Ireland would be monitored once Britain has left the EU’s customs union and the single market.

Lawmakers from the European Research Group (ERG), who oppose May’s so-called Chequers Brexit plan in favor of a harder break with the EU, said existing systems and technology could be used and any extra checks could take place away from the border.

“Rational, pragmatic approaches can ensure that the vital trade across the border is maintained. At the same time, this allows the United Kingdom to conduct an independent trade policy without threatening the integrity of the EU Single Market,” the lobby group said in a report.

May’s spokesman said the government had committed to not having a hard border and that it did not believe the answer was to move the border by carrying out checks elsewhere.

“We have been working on the issue of the Northern Irish border for two years and we have looked at a significant number of potential solutions and we believe that the plan put forward by Chequers is the only credible and negotiable one,” he said.

May’s Chequers proposal involves a common rule book for goods trade with the bloc.

“SIMPLISTIC AND IGNORANT”

The ERG said existing electronic procedures allowed customs declarations to be made ahead of travel, inspections can be done at the point of shipment and any additional declarations could be incorporated into the existing system used for VAT returns.

It also said licensed customs brokers could support businesses in dealing with rules of origin and customs arrangements.

“All of these solutions are reasonable solutions and are already in existence so could be scaled up pretty quickly,” Conservative lawmaker Maria Caulfield, a member of parliament’s Northern Ireland Affairs Committee, said at the report’s launch.

The ERG also said the government should agree equivalence of UK and EU regulations on agricultural products, something it said would be straightforward as the standards would be identical at the point the United Kingdom leaves the bloc.

Neale Richmond, a member of Ireland’s governing Fine Gael party and chairman of the upper house of parliament’s Brexit committee, described the report as “simplistic and ignorant”, saying most cross border trade in Ireland was done by small businesses who would be too burdened by bureaucracy proposed.

“These plans by a backbench rump of the Conservative Party are a mere distraction, they are poorly thought out and completely unworkable,” he said.

Nigel Dodds, Deputy Leader of Northern Ireland’s Democratic Unionist Party, which props up May’s Conservatives in parliament, welcomed the report, saying it showed the border issue should not prevent a free trade deal with the EU.

“Whether it is Chequers or whether it is a free trade agreement or indeed in the event of a no deal, you do not need infrastructure at the border,” he said.