Northern Ireland's former first minister has warned that the island of Ireland's post-Brexit relationship with the EU has created a dangerous imbalance.
Arlene Foster, former leader of the Democratic Unionist Party, was commenting on the Northern Ireland protocol.
Since January 2021 this has essentially meant that Northern Ireland is kept in the EU's Customs and single market, which Ms Foster is strongly against.
"Politics in Northern Ireland, between the UK and Ireland, and the UK and the EU, is out of balance, an imbalance created by the protocol," she told the regional assembly in Belfast, as she formally stepped down as leader of Northern Ireland.
"An imbalance and an instability is built in that will fester and deteriorate.
"Imbalance and instability in the context of Northern Ireland is a truly dangerous cocktail."
Anger over the protocol was followed by a week of rioting in Northern Ireland in early April, leading to at least 88 police officers being injured.
The EU has threatened the central government in London with reprisals if it extends a grace period on checks for chilled meat products, in a row that overshadowed last weekend's G7 meeting in Cornwall.
Prime Minister Boris Johnson has promised to do whatever it takes to protect the UK’s territorial integrity.
"Northern Ireland is part of the United Kingdom and needs to be treated as such,” Ms Foster said.
"If the EU does not, then the UK will have a practical, political and moral obligation to act to protect the everyday life of everyone in Northern Ireland.
"If Brussels continues to think that the protocol is enough, they are in denial … Over and out.”
Ms Foster was forced to step down in April after DUP members accused her of taking a soft stance against the border arrangements.
Her successor, Edwin Poots, has issued a warning that the situation in Northern Ireland was "very tense" after the April riots.