UK government increased threats to scrap parts of the Brexit agreement on Wednesday, claiming the deal is blocking the formation of a new government in Northern Ireland.

It sets Britain and the European Union on a collision course once again.

In the latest example of differences between the two sides, UK Foreign Secretary Liz Truss said the British government would "not shy away from taking action" if it is unable to come to an agreement with the bloc.

The EU warned that renegotiating the legally binding agreement "is not an option." Any move by the UK to unilaterally try to rewrite the deal would prompt legal action from the EU.

Northern Ireland protocol the sticking point

London and Brussels are at loggerheads over the Northern Ireland protocol, a deal which the British government agreed to before it left the bloc but now says is unworkable.

The deal effectively creates a customs border in the sea between Northern Ireland and the rest of the United Kingdom to preserve the province's open land border with EU member state Ireland.

The arrangement meant keeping the Irish border free of customs posts and other checks, because an open border is a key pillar of the Good Friday Agreement that ended decades of violence in Northern Ireland. Instead, there are checks on some goods entering Northern Ireland from the rest of Britain.

The arrangement is opposed by some of Northern Ireland's British unionists, who say the new checks undermine their British identity due to the barrier they create with the rest of the UK. The Democratic Unionist Party — which came second in last week's Northern Ireland Assembly election and sees itself as defending Britishness and Ulster Protestant culture against Irish nationalism while also being pro-Brexit — is non-compliant over helping form a government until the arrangements are substantially altered or ditched entirely.

Meanwhile, the vice president of Sinn Fein — which won the most seats in last week's elections — Michelle O'Neill warned earlier this week she "will not be held to ransom" by Brexit disputes holding up the formation of a new power-sharing government in Northern Ireland.

jsi/rt (AP, Reuters)