The Police Service of Northern Ireland says 41 of their officers have been injured during three nights of rioting in loyalist districts.
The trouble, which started in Belfast’s Sandy Row district, was triggered by the decision last week not to prosecute 24 Sinn Féin politicians - including Deputy First Minister Michelle O'Neill - for breaking COVID-19 rules when they attended the funeral of Provisional IRA veteran Bobby Storey.
More than 2,000 mourners attended the funeral of Storey, the IRA’s former intelligence chief, on 30 June 2020 and unionists claimed they blatantly ignored social distancing rules at the height of the first wave of the pandemic.
The decision led to all the main pro-British parties - the Democratic Unionist Party (DUP), Ulster Unionist Party (UUP), Traditional Unionist Voice (TUV) and Progressive Unionist Party (PUP) - to call for the resignation of the PSNI’s chief constable.
Young men in staunchly loyalist parts of Belfast, Londonderry and smaller towns like Newtownabbey and Portadown spent Saturday, Sunday and Monday night pelting police with bricks and petrol bombs.
But what lies behind all the anger and how easy would it be for Northern Ireland to slip back into the mire of sectarian violence which gripped it between 1969 and 1998?
First some simple facts.
On 3 May 1921 - 100 years ago next month - Northern Ireland was created as a legal entity under the Government of Ireland Act 1920.
Under that legislation the Irish Free State - later to become the Republic of Ireland - came into being and the six counties of Antrim, Armagh, Down, Fermanagh, Tyrone and Londonderry - were carved off and remained part of the United Kingdom.
Northern Ireland is often referred to as Ulster, although historically Ulster also included County Donegal, County Monaghan and County Cavan.
For almost half a century there was peace in Northern Ireland but the Catholic minority claimed they were discriminated against when it came to jobs, housing and political power and in the late 1960s the IRA launched a terrorist campaign.
Loyalist Protestant gangs like the Ulster Volunteer Force (UVF) and Ulster Defence Association (UDA) carried out hundreds of killings as they clashed with the Provisional IRA and the socialist INLA.
By the mid-1990s loyalist paramilitaries were killing more people than the Irish republicans and the IRA’s political wing Sinn Fein faced up to the fact that it could not force Britain out by military means.
Secret negotiations began under John Major’s Conservative government and after the Labour Party won a landslide election victory in 1997 Prime Minister Tony Blair decided to make a political solution in Northern Ireland one of his top priorities.
Eventually the Good Friday Agreement was hammered out and approved by referendums in both Northern Ireland and the Republic of Ireland.
The agreement kept Northern Ireland as part of the UK but created a power-sharing government which meant the DUP and Sinn Fein, as the two parties with the most votes, ended up running the six counties of Ulster together.
IRA, INLA, UVF and UDA prisoners were freed - including many who had committed heinous crimes - the Royal Ulster Constabulary was scrapped and replaced by the PSNI and the agreement also said the island of Ireland could only be united if a majority in Northern Ireland voted for it in a border poll.
At the last census, in 2011, 48.4 percent of the population identified as Protestant and 45.1 percent as Catholic, so it seemed unlikely a majority would vote for a united Ireland.
It will be interesting to see, in this year’s census, whether Catholics are now in a majority and there has been speculation that many Protestants are now in favour of a united Ireland, especially following the Brexit referendum which has left them outside of the EU but the Republic still in it.
Although the DUP campaigned for Brexit, Boris Johnson’s government forced through a deal with the EU which effectively created a new trade border in the Irish Sea, something which has also enraged unionists and loyalists.
The UK-EU trade deal imposed customs checks on goods moving between Northern Ireland and the British mainland.
The deal was designed to avoid checks at the border between Northern Ireland and the Republic of Ireland, something which could have undermined the Good Friday agreement.
The DUP has been calling for the Brexit deal to be scrapped but in the shadows the UVF and the UDA are believed to be recruiting among young Protestants, many of whom were not even born when the Good Friday Agreement was signed.
Mark Lindsay, chairman of the Police Federation of Northern Ireland, said the “political atmosphere” was being exploited by the loyalist paramilitary groups, which had faded into the background in the last 20 years.
Mr Lindsay told the BBC: "Older, more sinister, elements use the youth and use children to achieve their aims."
In October 2019 Paul, an Irish republican from Derry who served time for possessing petrol bombs, told Sputnik: "The loyalist paramilitaries will start killing Catholics if a united Ireland ever looks likely."
There are also fears that some on the Irish republican side are ready to go "back to war".
In July 2020 a joint police and MI5 operation led to the arrest of several people who were allegedly attending a meeting of the New IRA in Omagh, County Tyrone.
Many of those who lived through The Troubles are terrified the current political tensions between Sinn Fein and the DUP could tip over into violence and send Ulster hurtling back to a time of sectarian terror and hatred.