The outbreak of violence in Northern Ireland is a "direct consequence of Brexit" and the "lack of attention in London to the problems" in the province, former Irish prime minister John Bruton has told Euronews.
Bruton also blamed the violence on the actions of the Sinn Féin party and the recent calls for Irish unification.
The turmoil has spread to other cities in the north, such as Londonderry, Carrickfergus, Ballymena and Newtownabbey.
The riots follow rising tensions between loyalists (Catholic) and unionists (Protestant) over how post-Brexit trade rules are being implemented in Northern Ireland.
"Unionists are rising up right now because they see the introduction of some border controls within the union, as they say," Bruton, who served as Taoiseach (Prime Minister of the Republic of Ireland) from 1994 to 1997, told Euronews.
"And they feel that any controls, even controls of a highly bureaucratic character, that these symbolise for them a weakening of the union between Northern Ireland and the UK.
"And symbols, unfortunately, are enormously important to Northern Ireland. It's very often it's the symbols rather than the reality of life that influence people. And that's the legacy of 400 years of strife."
Besides disagreements over Brexit, the violence is also being fuelled by worsening relations inside the Protestant-Catholic power-sharing Belfast government.
The breaking point came last week when Northern Ireland's prosecutor decided not to prosecute the people involved in the funeral of republican Bobby Storey.
The service took place last June and was attended by over 2,000 mourners, including several key figures of the Sinn Féin party, a left-wing Irish republican party, despite coronavirus regulations that imposed strict limits to public gatherings.
"[The violence] is a direct consequence of Brexit, but it's also a consequence of other things, [like the] failure on the part of Sinn Féin during a funeral to take into account the public health code restrictions and the non-prosecution of people for those offences. That has inflamed the public opinion," the former Fine Gael politician said.
"And there is also a campaign being generated in favour of having a poll on Irish unity, which would be deeply divisive in Northern Ireland. You would have half the community for it and half the community against [it]. When you get down to issues of territory and unity, that is an existential question that is deeply, deeply divisive and destructive."
'Boris Johnson is being irresponsible'
The unrest, which has left more than 40 police officer injured, is seen as a direct threat to the Good Friday Agreement, a 1998 peace accord that put an end to the 30 years of ethno-nationalist conflict in Northern Ireland that killed more than 3,500 people.
The Troubles, as the bloody period is known, started "with rioting in the late 60s and it gradually escalated into something far, far worse than rioting," says Burton. "There is a risk that we're into the same cycle again. And it is because of the lack of attention in London to the problems of Northern Ireland."
"There's been a lack of attention to unionist sensitivities and national sensitivities in respect of [Brexit]. Remember, the people of Northern Ireland voted against Brexit, but Brexit is being imposed upon them because the people of England are more numerous and they were for Brexit."
British PM Boris Johnson, Northern Ireland's First Minister Arlene Foster and Irish Taoiseach Micheál Martin have already condemned the rioters and appealed for calm. The European Commission and the administration of US President Joe Biden have expressed similar concerns.
Bruton believes the current situation is the result of the "haste" in which the negotiations between the European Union and the United Kingdom were conducted.
"[Boris Johnson] is being irresponsible. He denied reality. He denied the meaning of things that he'd agreed to, which I think displays an inexcusable lack of attention to detail on the part of the prime minister," he remarks.
"Boris Johnson, and the Conservative Party more generally, has been responsible for the haste with which all this was negotiated. They rushed all the deadlines, they wanted early deadlines for conclusion, they wanted out of the EU as fast as possible."
The former Taoiseach thinks Johnson's government put too much focus on the identity politics of Brexit instead of on its practical ramifications.
"The UK government used and saw Brexit as an expression of English identity rather than as a practical project. They didn't go into the detail of what Brexit would mean. And now, in a way, they're discovering what Brexit means, having treated it mainly as a sort of an emotional expression, there are now discovering that it has lots of very difficult practical workings, which they haven't come to terms with," Bruton says.
"And as they discover these, they're trying to withdraw from them unilaterally without taking into account of the fact that the withdrawal agreement is an international treaty. And there is some doubt now: will the European Parliament even ratify the trade deal with Britain? Because Britain is proving not to be reliable as an implementer [of the deal]."