Hundreds of English and Scottish police officers could be deployed to combat unrest in Northern Ireland after a no-deal Brexit.
The Police Service of Northern Ireland (PSNI) has started drawing up plans to call in reinforcements from across the Irish Sea.
Authorities in Belfast fear that their 6,600-strong police force could be overwhelmed should a no-deal Brexit in March lead to the border with Ireland being hardened.
Northern Irish leaders have repeatedly warned that returning to a hard border could provoke civil unrest and even violence.
The former chief constable of the PSNI, Sir Hugh Orde, has previously said failing to keep the border open would “play into the hands of those who are still determined to destroy the relative peace that we have enjoyed through close co-operation and effective policing since the Good Friday agreement”.
Border controls and new facilities could be easy targets for dissident republican paramilitaries, others have warned.
George Mitchell, a former US senator who was a key broker of the peace process, said last year a hard border could turn the clock back on decades of progress.
“The real danger is if you reinstate a hard border, you go back to the days where stereotyping resumes, demonisation resumes and people turn inward as opposed to outwards.”
Training for officers who could be deployed to Northern Ireland is expected to begin this month, The Guardian reported.
In a statement, Chief Superintendent Simon Walls from the PSNI said his force was “working closely with other UK policing partners in our Brexit planning processes”.
“Mutual aid would only be sought if absolutely necessary, however sensible precautionary preparations for it do form part of our ongoing planning work.”
Police forces in Britain regularly lend officers to other organisations to cover short-term needs, a process known as mutual aid.
The PSNI has previously requested extra manpower from British forces to help them police Northern Ireland’s contentious marching season.
During the 2011 riots as many as 1,000 specialist riot-trained officers from across Britain were sent to other jurisdictions to support embattled local forces.
A statement from the National Police Chiefs Council said: “Police forces continue to prepare for possible eventualities as exit from the European Union draws nearer.
“As it stands, we have not received a formal request for mutual aid support from Police Service Northern Ireland.”
The assistant chief constable of Northern Ireland, Mark Hamilton, tried to downplay the likelihood of the PSNI having to call for mutual aid in a later statement.
“At the present time, we do not have any reason to believe we will need to request mutual aid during 2019, but putting precautionary procedures in place for it is part of a sensible planning process,” he said.
“Normally the plans are in place for the summer months, but this year, additional resources will be available from the date of the EU Exit at the end of March, in line with national contingency planning.
“Our view is that it is better to have precautionary plans in place and not use them, than find we may need additional police support but cannot have it because we have not alerted the National Police Coordination Centre [NPCC] in advance.”
But the possibility of large numbers of English and Scottish officers patrolling streets in Northern Ireland is likely to inflame community tensions.
The province voted to remain in 2016’s referendum with a majority of 56 per cent, and border communities in particular have complained about being forced out of the EU against their will.
But others are less perturbed. A poll conducted last summer found 33 per cent of Northern Irish people think the “unravelling of the peace process” would be a price worth paying to leave the EU.
This figure rises to 87 per cent among those who voted Leave.
However, the communities who live along the border tended to vote Remain and are also more likely to be republicans who favour a united Ireland.
Currently, there is no infrastructure or border controls when crossing between Northern Ireland and the Republic of Ireland, but if Britain quits the bloc without a deal, goods moving between the two territories will be leaving and entering the EU’s single market and customs union and will need to be checked.
Theresa May met with senior figures in the Democratic Unionist Party (DUP) on Thursday in a vain effort to get the Northern Irish party – which has been propping up her minority government – to back her proposed deal with the EU.
But the DUP has said it still will not vote for the prime minister’s deal, mostly because of the Northern Irish backstop.
Nigel Dodds, the party’s Westminster leader, denied there would need to be a hard border even if the UK fails to secure a deal by Brexit day on 29 March.
This is widely contradicted by experts who have said that both London and Dublin would have no choice under international law but to reimpose a hard border.
The party’s Brexit spokesman, Sammy Wilson, dismissed the news of the PSNI’s preparations as “old tactics” being used to create unnecessary alarm over a no-deal Brexit.
“It is important that people do not needlessly create alarm. From the secretary of state to Michael Gove and anyone else the government can persuade, we are subjected to a daily diet of how cataclysmic it would be to reject the prime minister’s withdrawal agreement,” he said.
“Such tactics are as fruitless as they are transparent. They didn’t work before Christmas and they won’t fool parliament now either.”
Other police forces have signalled a no-deal scenario would put them under serious strain.
Kent Police have already confirmed none of their officers are allowed to take any leave for a month after 29 March.
There are fears a no-deal Brexit would cause huge traffic jams across Kent as freight lorries heading to the continent through Dover backed up, and possibly even disorder at ports amid the chaos.
A leaked document prepared by the NPCC revealed there was a “real possibility” that police forces would have to call on the military to help deal with civil unrest caused by a no-deal Brexit.
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