A bomb found beside a car in County Derry was put there in an attempt to kill a police officer and her toddler daughter, police have said. The Police Service of Northern Ireland (PSNI) confirmed a viable explosive device attached to a container of flammable liquid had been found on Monday evening outside the part-time officer’s home in a rural part of the county. The Northern Ireland secretary, Brandon Lewis, described the incident as an “attempted murder”. The PSNI assistant chief constable Mark McEwan said: “This was designed to cause a fireball which would have engulfed the victim’s car and anyone in it or close by. “What is really distressing here is the terrorists placed the bomb at the rear of the car directly at the point where the victim’s three-year-old daughter sits. This demonstrates the complete and utter disregard for the life of a mother and her toddler – this simply beggars belief.” There was no immediate claim of responsibility for the attack but police believe the New IRA dissident group is behind the attack, its first in over a year. The incident threatens to further escalate tensions in the region, which has been rocked by a spate of violence and rioting over Easter partly driven by opposition to Brexit checks on goods being shipped in from Great Britain. On Tuesday, Boris Johnson pledged to cut the “ludicrous” border checks and get “the barnacles off” the Northern Ireland protocol. The prime minister told BBC Northern Ireland’s Spotlight: “What we are doing is what I think is removing the unnecessary protuberances and barriers that have grown up and we are getting the barnacles off the thing and sandpapering into shape. “If it looks as though the EU is going to be very dogmatic about it and we continue to [be in an] absurd situation so you can’t bring in rose bushes with British soil into Northern Ireland, you can’t bring British sausages into Northern Ireland, then frankly I’m going to, we’ll have to take further steps.” Others were quick to point out that the checks were a direct result of the hard Brexit that Johnson had pursued. Maroš Šefčovič, the European commissioner overseeing Brexit issues, said: “This agreement was negotiated signed and ratified by the government of Prime Minister Johnson. When it comes to some of the claims, what I have to say here is that all of them are consequences of the Brexit, the type of Brexit, which was chosen by the British government. “All the examples … could be very easily resolved if the United Kingdom would have decided to stay in the area of sanitary and phytosanitary controls. So here we are dealing with, with the consequences of Brexit.” Šefčovič said the commission was, however, in talks with the UK government over making the implementation of the checks more palatable in light of the violence of recent weeks. “Of course, what we want to make sure is that we would minimise the disruption for the people in Northern Ireland but it has to be a two way street,” he said. “We are ready to do our parts, but I’m sure that the UK can do more, and this is what we would like to discuss and what we are discussing with our British counterparts. “The checks could be smoother, if we finally do get appropriate access to the IT system for customs checks. A lot of these controls could be removed if it would find the solution on respecting well-regarded standards for food protection, for phytosanitary controls and for all the issues linked to such important elements as public safety, public health and animal welfare. “All these things we proposed to the UK government at the time of the negotiation of withdrawal agreement and the trade deal – as you know very well they’ve been rejected, and therefore, now we go through very demanding negotiations, how to implement it on the ground.” If Johnson were to take the step of invoking article 16 of the protocol it would be hugely confrontational. Relations with the EU have yet to recover after an official in Brussels threatened such a move in January in relation to vaccine supplies. Officials in London and Brussels are engaged in intense technical talks to smooth the application of the protocol, which has polarised views in Northern Ireland. Nationalist political leaders and many business leaders want to make it work and argue that if a pragmatic approach is found to checks then the region could have the best of both worlds, allowed to trade both in the EU and the UK without trade barriers. However, loyalist and unionist leaders want it scrapped and it contributed to Easter’s rioting. The DUP peer Nigel Dodds last week described the EU’s approach as “belligerent” claiming it had “ignored the view of unionists and trampled all over the founding principles of the devolved settlement” including the principle of consent of all communities. The attempt to blow up a police officer’s car was denounced across the political spectrum, with Lewis describing it as “absolutely abhorrent” and the shadow Northern Ireland secretary, Louise Haigh, calling it “reprehensible”. In a statement, McEwan said: “We are treating this as an attack on a member of staff who also serves her community as a part-time officer.”