Members of the European Parliament and the House of Commons are meeting today in Brussels to discuss the war in Ukraine and the impact of the Brexit deal on both sides of the English Channel.
The occasion marks the first meeting of the EU-UK Parliamentary Partnership Assembly (PPA).
It comes in the midst of growing speculation regarding the future of the Northern Ireland Protocol, a key element of the Withdrawal Agreement that enables trade between the two sides of the Irish border.
The government of British Prime Minister Boris Johnson has repeatedly argued the protocol is unworkable and has for months tried to renegotiate the text, despite having agreed to its initial form.
Tensions have ratcheted up in recent days after Sinn Fein, a republican party that support Irish reunification, won the largest number of seats in the Northern Ireland Assembly for the first time.
The surprising victory led the Democratic Unionist Party (DUP) to announce it will not join the new power-sharing executive unless the special post-Brexit status on the border is amended.
The EU and the US have warned London against single-handedly changing the protocol, which they views as essential to maintain peace on the island and honour the Good Friday Agreement.
"No one should unilaterally cancel, break or in any way attack the settlement we have agreed together," German Chancellor Olaf Scholz said this week.
Despite the fraught atmosphere, the protocol won't be the top item on the EU-UK joint agenda.
The two-day meeting will begin at 2:30 PM CET with an opening statement by Roberta Metsola, the president of the European Parliament.
Lawmakers will then exchange views with Maroš Šefčovič, the vice-president of the European Commission who oversees EU-UK relations, and Michael Ellis, minister for the cabinet office form the British government.
British Foreign Secretary Liz Truss will not attend but held a phone call with Šefčovič ahead of the meeting. According to a read-out released by the Foreign Office, Truss said the protocol "had become the greatest obstacle to forming a Northern Ireland Executive" and was causing "unacceptable disruption to trade."
Despite the fraught atmosphere, the central issue on Thursday will be Russia's invasion of Ukraine, a crisis where both sides have found plenty of common ground over the past three months.
The EU and the UK, together with Western allies, have worked closely and intensively to maintain a united front against President Vladimir Putin and slap a hard-hitting raft of coordinated sanctions.
This week, Boris Johnson pledged his country will defend Sweden and Finland, two EU member states that don't belong to NATO, if either country comes under attack.
The joint assembly will resume on Friday morning, this time to focus on energy cooperation, the general state of EU-UK relations and the impact of the Brexit deal.
Although the Northern Ireland Protocol is not mentioned by name on the agenda, it is expected the topic will be discussed in the context of the ongoing tensions.
The EU-UK Parliamentary Partnership Assembly comprises 70 lawmakers, 35 from each parliament, and is co-chaired by Nathalie Loiseau, a French MEP who sits with the liberal group Renew Europe, and Sir Oliver Heald, a Conservative MP for North East Hertfordshire.
It was set up after the EU-UK trade agreement entered into force in January 2021.