Brussels warned that its trade deal with the UK would allow the EU to hit British goods with tariffs if Boris Johnson fails to honour post-Brexit obligations on Northern Ireland, as MEPs moved to ratify the treaty.

European Commission president Ursula von der Leyen told the European Parliament on Tuesday, ahead of the vote to approve the 1,449 page trade and co-operation agreement, that the deal would equip the bloc with new ways to exert pressure on Britain.

She said this included extra powers to address violations of the so-called Northern Ireland protocol, part of the 2019 Brexit deal, which avoids a hard border on the island of Ireland. The protocol means the creation of a trade frontier in the Irish Sea, which even before its full implementation has led to disruption and friction for businesses in the region, contributing to a wave of unrest.

MEPs earlier this year put ratification of the trade agreement on hold in protest against threats by the UK government unilaterally to extend the grace period to implement the protocol. Last month, the European Commission launched legal action against the UK after it granted extended waivers from some of the protocol’s rules.

Von der Leyen told MEPs that ratification would “give us the tools we need to ensure full and faithful compliance with the obligations which both sides signed up to”, adding that it would “also focus minds on finding pragmatic solutions where they are needed, most urgently around the [Northern Ireland] protocol”.

MEPs are expected to approve the text of the trade deal — which has been in provisional force since Britain left the EU single market at the end of 2020 — by a comfortable majority when voting opens on Tuesday evening, clearing the way for its formal adoption by the EU.

Britain’s trade deal with the EU was sealed during frantic negotiations in the last days of December 2020. The UK parliament voted the agreement through in a single day in order to ensure that its benefits, including tariff-free trade on British and EU-made goods, were in place for the end of the country’s post-Brexit transition period. But the European Parliament insisted on more time for scrutiny.

Maros Sefcovic, the EU’s Brexit commissioner, told MEPs that the powers in the trade deal that could be used to hold the UK to account included “cross retaliation and suspension of market access in the case of breach of the good faith obligation to implement the withdrawal agreement, including the protocol”.

The result of the parliament vote will be announced on Wednesday morning.

Both sides are under pressure to find ways to ease tensions in Northern Ireland caused by the protocol arrangements, which have been denounced by the region’s unionist politicians. Along with paperwork and checks on trade, other irritants have included problems with parcel deliveries and restrictions on travelling with pets.

Von der Leyen said she was “glad to report some progress” in talks with the UK on a joint implementation plan, adding that “in recent days and weeks we have seen a new constructive dynamic”.

“The next step is to mutually agree on a compliance path with concrete deadlines and milestones,” she said. “The EU is steadfast in its determination to make it work.”

Tuesday’s vote was also an opportunity for the EU’s former Brexit negotiator, Michel Barnier, to reflect on the outcome of four years of talks with the UK.

Britain’s decision to leave was a “warning,” he said. “It’s a failure of the EU, and we have to learn the lessons.”