Downing Street has defended plans to give British ministers unilateral powers over Brexit arrangements in Northern Ireland, putting them on a collision course with the EU and Irish leaders in a week of crunch negotiations. A No 10 spokesman said the measures were “limited and reasonable” and insisted the UK would remain compliant with the Northern Ireland protocol – despite anger from Brussels and Dublin at the plans leaked overnight. Ursula von der Leyen, the president of the European commission, warned Boris Johnson not to break international law and the EU’s chief negotiator, Michel Barnier, also reiterated that the EU “demand[s] quite simply, and calmly, and until the end, that the political commitments in the text agreed by Johnson be legally translated into this treaty”. Johnson’s spokesman said the peace process or the UK’s internal market could “inadvertently be compromised by unintended consequences of the protocol”. He said the steps taken in two forthcoming bills would “clarify specific elements of the Northern Ireland protocol in domestic law to remove any ambiguity” and said it would deliver on a manifesto commitment to ensure Northern Ireland’s businesses and producers enjoy unfettered access to the rest of the UK. Government sources said they needed legislation to give ministers powers to fully implement the protocol after Brexit, something that has astonished the Irish government, which is 100% happy that the protocol is legally watertight. A UK official admitted this would set Britain on a collision course with the EU with “some debate in the EU legal profession who will want clarity on how it will work vis a vis direct effect”. This is a reference to the EU laws that allow individuals or companies to sue, which will disappear in the UK after Brexit but will continue to apply in Northern Ireland under the special Brexit protocol. Catherine Barnard, a professor of European law at Cambridge University, said: “This is politics over law. I think they are trying to make it clear to the EU that they need to make some movement in the talks and they are using something as sensitive as the Northern Ireland protocol in order to precipitate that. But it is a very high-stakes gamble.” A UK official briefed on the new powers, which will be set out in the internal market bill and the finance bill over the coming weeks, said Westminster did not believe the new powers undermined the NI protocol agreed in December – a statement likely to be hotly contested in Brussels. “The government is completely committed, as it always has been, to implementing the NI protocol in good faith,” a UK official said. “If we don’t take these steps we face the prospect of legal confusion at the end of the year and potentially extremely damaging defaults, including tariffs on goods moving from GB to Northern Ireland. “We are making minor clarifications in extremely specific areas to ensure that, as we implement the protocol, we are doing so in a way that allows ministers to always uphold and protect the Good Friday peace agreement.” It is understood officials have advised that these powers must be introduced in the internal market bill and the finance bill, before negotiations conclude, in order to complete the legislation before the transition period finishes at the end of the year. Under the withdrawal agreement, Northern Ireland will stay in the EU’s single market regardless of whether there is a new deal with the EU on trade and security by the end of the year, including its rules on state subsidies for businesses, known as state aid. The bloc’s customs code will also be implemented in full on goods coming into the province from the rest of the UK, requiring checks. However, the legislation planned by the UK government seeks to very narrowly define the obligation to notify Brussels of subsidy decisions for it to approve. Clauses in the bill could also dispense with the requirement for local businesses to file customs paperwork when sending goods into the rest of the UK. A Downing Street spokesman said the UK was committed to the protocol regardless of achieving a deal and that Johnson had been consistent about how he would proceed. “The PM has always been publicly clear about what our interpretation of both the withdrawal agreement and the Northern Ireland protocol was, he publicly set out there would be no export summary declarations on goods moving from Northern Ireland to Great Britain and he also ruled out tariffs on goods moving from GB to NI on several occasions,” the spokesman said. “He set out those positions in advance of the EU signing agreement.”