UK Foreign Secretary James Cleverly on Wednesday met Northern Ireland politicians to try to break months of political deadlock over post-Brexit trading rules and end a boycott of the power-sharing assembly in Belfast.
Cleverly said afterwards it was "essential that we find a solution" to the divisive Northern Ireland Protocol, which has angered pro-UK unionist parties and seen them refuse to sit at the body unless the rules are overhauled or scrapped entirely.
He called the talks, after a potential breakthrough agreement between London and Brussels over customs data sharing this week, "important and timely".
But hopes were dashed of further progress as he was left to meet just unionists and the non-sectarian Alliance party because of a row over who could attend.
The talks did not include representatives from pro-Irish party Sinn Fein, which withdrew after its Ireland leader was shut out, prompting fellow nationalists the SDLP to follow suit.
Sinn Fein accused the UK of "excluding" its president Mary Lou McDonald, even though her deputy Michelle O'Neill, who stands to become Northern Ireland first minister, was invited.
"This meeting is for Northern Ireland politicians," a spokesman said. McDonald called it "bizarre and unacceptable" but Cleverly blamed a protocol issue.
- Hopes -
Under the Northern Ireland Protocol, goods heading to the province from mainland Great Britain need customs checks to ensure they do not enter the European single market via member state Ireland.
But opposition from the Democratic Unionist Party (DUP) has left Northern Ireland without a power-sharing government between nationalists and unionists, imperilling the backbone of a 1998 peace deal.
There are hopes the stand-off can be resolved before the 25th anniversary of the signing of the Good Friday Agreement, which ended three decades of sectarian violence over British rule and created an open border between Northern Ireland and Ireland.
Brussels and London have negotiated for months to soothe tensions surrounding the protocol, with unionists angered at what they see as unnecessary checks on goods in the internal UK market.
They maintain that the arrangement -- keeping Northern Ireland in the EU customs union and single market -- casts it adrift from the three other UK nations and makes a united Ireland more likely.
Former prime minister Boris Johnson strained EU-UK relations by seeking to unilaterally overhaul the protocol through a draft law still wending its way through parliament.
- Looming deadline -
On Monday, the UK and the 27-member bloc agreed on EU access to live information about which goods are moving across from Great Britain to Northern Ireland.
On Tuesday, Irish foreign minister Micheal Martin met the EU pointman on the issue Maros Sefcovic for what he called "very useful discussions" and said he was "encouraged by the new positive momentum" to resolving the dispute.
Ireland's premier, Leo Varadkar, is due to hold meetings with Northern Ireland's political leaders tomorrow.
The trip by Varadkar, who was in power when the protocol was agreed, is his first since he returned to the office of Taoiseach (prime minister) in December.
Last week he told reporters he believed mistakes had been made on "all sides" in the way Brexit had been negotiated.
UK opposition Labour leader Keir Starmer is also due to be in Northern Ireland on Thursday for meetings with party leaders.
The flurry of visits to Belfast comes ahead of a looming January 19 deadline for the resumption of the power-sharing government at Stormont.
The UK government has warned it could call fresh elections in the face of the DUP boycott but has also legislated to potentially extend the deadline to a later date.