Northern Ireland’s Democratic Unionist party has elected regional agriculture minister and young earth creationist Edwin Poots as its next leader after he narrowly defeated Westminster MP Jeffrey Donaldson.

Poots will replace Arlene Foster as the leader of the region’s largest political party at the end of May but has said he does not want to take on her other role, Northern Ireland’s first minister, which she relinquishes a month later.

The DUP confirmed 55-year-old Poots’ election by the party’s representatives at Westminster and the Northern Ireland assembly at Stormont on Friday afternoon. He was the favourite going into the count and beat Donaldson by 19 votes to 17.

Known for his hardline views, people close to Poots have said he will take a tougher line on opposing the Northern Ireland protocol to the Brexit trade deal, which sets a customs border in the Irish Sea. The disruption caused by the protocol was a key factor in the move to oust Foster two weeks ago.

Speaking after the first leadership contest in the DUP’s 50-year history, Poots said he would reach out to other unionist leaders to co-ordinate their efforts against the trade arrangements, which he said had proven a “massive challenge”.

“If we are to fight this to ensure that everybody in Northern Ireland is not worse off as a consequence of the protocol then it’s for us to do that together . . . [without] the unionist bickering that we have had in the past,” he said.

Describing opposition to the protocol as an issue identified by “every unionist”, Poots told reporters at Stormont that he would speak with Brandon Lewis, the UK government’s secretary of state for Northern Ireland, on Friday evening and meet him in Belfast next week.

“I intend to be in London later next week to continue those discussions with government,” he added, refusing to answer questions.

In his current role as agriculture minister, Poots boycotted meetings of the North-South ministerial council of Northern Ireland and Republic of Ireland leaders as a means of expressing his opposition to the protocol.

Irish taoiseach Micheál Martin on Friday evening congratulated Poots. “His appointment comes at a critical time when it is ever more important for us to work together to keep the peace process firmly on track and to promote prosperity on both a North/South and East/West basis,” Martin added.

The DUP’s leadership announcement included no details around who would be the next first minister. Poots told the FT earlier this month that he would not take the role and might not even stay on as agriculture minister because his focus would be on the party. He said the DUP would select the first minister.

Poots has been billed as a divisive figure, with conservative views on social issues. A senior DUP insider who had previously backed the Foster leadership expressed dismay at the decision to elect Poots, who appealed to the party’s ideological base but not the wider electorate. “This is the DUP’s Jeremy Corbyn moment and we all know how that ends,” he said, referring to the former UK Labour party leader who in 2019 oversaw its worst election defeat in decades.

Poots on Friday said he was “looking forward to a positive relationship right across Northern Ireland with my party colleagues and indeed people from other parties”.

“The great thing in Northern Ireland is the resilience of all of its people,” he said, speaking of plans to improve education and health. “There’s much to do, much to be done,” he said.

Paula Bradley, a member of the Stormont assembly, was elected deputy leader by a margin of 18 to 16 votes. Two of the votes cast were invalid.

The result came after the taoiseach held talks with the UK prime minister at the latter’s country seat, Chequers — the first face-to-face meeting between Martin and Boris Johnson since August 2020.

The pair held wide-ranging discussions, including the emergence from Covid-19 lockdown, and how to provide justice for victims of the three decades of sectarian violence that roiled Northern Ireland until the 1998 Good Friday peace deal was signed.

They also discussed the implementation of the trade protocol.

In a joint statement released after the talks, they agreed to continue “working together to uphold the Belfast/Good Friday Agreement” and also to “maintain smooth trade” between Great Britain, Northern Ireland and the Republic of Ireland.

As the two leaders met, a unionist grouping opened a High Court legal action in Belfast seeking a judicial review of the protocol.

Launching the challenge, John Larkin QC told the court that the protocol was “unlawful on a number of grounds”, including that it treated Northern Ireland differently to the rest of the UK by imposing a border in the Irish Sea.