Security stops anti-Brexit activist Steve Bray approaching Britain's main opposition Labor Party leader Keir Starmer (unseen) as he walks along the seafront to attend an interview, on the second day of the annual Labor Party conference in Brighton, southern England on Sunday. Photo: AFP

Belfast's Appeal Court ruled Monday that a Brexit protocol between Brussels and London is lawful, blocking a bid to scrap the controversial arrangement which governs trade in Northern Ireland.

The protocol - part of the UK's divorce deal with the EU - has proved deeply unpopular with Northern Ireland's pro-UK unionist politicians, who launched the legal challenge.

Lawyers for the unionist politicians, including former Democratic Unionist Party (DUP) and Ulster Unionist Party (UUP) leaders, are expected to launch an appeal to Britain's Supreme Court after the case was also rejected by the High Court in Belfast in June.

They have argued the Brexit legislation is incompatible with the 1998 Good Friday Belfast Agreement, which ended three decades of violence over British rule in the province.

Their legal teams also sought to scrap the protocol on the grounds it was incompatible with the 1800 Act of Union which merged the kingdoms of Britain and Ireland. However, Lady Chief Justice Keegan dismissed both cases.

Ahead of elections to Northern Ireland's devolved assembly in May, the province's politics have been plunged into crisis by issues surrounding the protocol.

In February, Paul Givan, the unionist leader of Northern Ireland's power-sharing executive, resigned from his position in protest against the post-Brexit trade mechanism, prompting the collapse of the devolved government. 

The move has further complicated post-Brexit negotiations between Brussels and London - which has said it is also opposed to the protocol.

Issues surrounding the protocol overshadowed a recent visit by Irish prime minister Micheal Martin to London, where the Taoiseach looked to show a united front with British Prime Minister Boris Johnson over the Ukraine crisis. 

AFP