By Emma Patterson Since the signing of the Good Friday Agreement, Anglo-Irish relations had gone from strength to strength.
But then came Brexit.
The United Kingdom's protracted exit from the EU and the controversial issue of the Northern Ireland protocol have driven a wedge between the UK and the Republic of Ireland, and shattered trust between the two nations.
Strained relations haven't gone unnoticed on the world stage, with tensions rippling across the Atlantic.
An influential group of US politicians, led by Congressman Richard Neal, are visiting the UK and the Republic of Ireland to reaffirm America's 'unwavering support' for the Good Friday Agreement.
Dublin and London appear poles apart on the protocol.
Former Secretary of State Lord Peter Hain said: "It's deeply depressing to see the complete breakdown of trust between Dublin and London.
"There are smiles in public when people shake hands at various events but the truth is behind the scenes Dublin does not trust London, nor does Brussels, and frankly I don't blame them."
WATCH: The DUP's Gordon Lyons, the SDLP's Claire Hanna and NI Affairs Committee Chair Simon Hoare discuss the Protocol:
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