Boris Johnson has rejected Brussels’ latest attempt to iron out problems with the post-Brexit arrangements for Northern Ireland, insisting that the withdrawal agreement signed last year must be renegotiated. A series of proposals published by the European Commission on Monday with the aim of easing implementation of the Northern Ireland protocol were said to be insufficient for the scale of the problems. A UK government spokesperson said the two sides instead needed “comprehensive and durable solutions”. David Frost, the minister responsible for Brexit issues, has said that without a major change to the legal text of the protocol, the government will consider triggering article 16 of the EU-UK agreement to suspend parts of the deal. Such a move would be permitted where it can be shown that “serious economic, societal or environmental difficulties” are arising. But the commission would probably challenge such a decision. It would be likely to go to arbitration, raising the risk of trade sanctions down the line. The government issued a command paper last week detailing the key changes it wishes to make to the arrangements under which Northern Ireland in effect stays in the EU’s single market and the bloc’s customs rules are enforced on goods passing across the Irish Sea. The UK government spokesperson said it was only by engaging with Downing Street’s demands that the issues relating to a range of problems, which have caused political instability and violence in Northern Ireland in recent months, could be solved. However, he said what the EU proposed represented “only a small subset of the many difficulties caused by the way the protocol is operating”. “We need comprehensive and durable solutions if we are to avoid further disruption to everyday lives in Northern Ireland,” he added. The UK’s outright rejection on Monday of the commission’s overtures on some of the difficult issues, including the flow of medicines from Great Britain to Northern Ireland and the movement of guide dogs and cattle, further sets the two sides on a collision course. A series of grace periods are due to end in October and in January next year, while the commission has insisted that it will not rewrite the legal text agreed with Johnson in 2019. Lord Frost has insisted that he is sincere in wanting the protocol to be successful but that he cannot envisage a situation that will gain the support of all communities in Northern Ireland without a new negotiation on the text. The command paper issued last week had suggested that political pressures in 2019 forced the government to agree to the protocol and sign it in 2020. Loyalist groups have claimed that the protocol is undermining their British identity by creating barriers to trade within the UK. The commission has suggested it rewrite its own laws to allow UK regulators to approve medicines destined for Northern Ireland – but strictly on the basis that they would implement EU law. A UK government spokesperson said the proposal still fell short. “The EU’s proposal was a welcome start but it would be complex to operate, onerous and would not deal at all with those medicines, such as new cancer drugs, which under current arrangements must be licensed by the European Medicines Agency in Northern Ireland,” he said.