Edwin Poots, the Democratic Unionist party (DUP) leader, has named his party colleague Paul Givan as the next first minister of Northern Ireland. Poots made the widely expected announcement in the Great Hall at Stormont on Tuesday amid turmoil within the DUP that threatens to destabilise the power-sharing executive and assembly at Stormont. Givan, 39, an assembly member from Poots’s own Lagan Valley constituency, is to take the post on Monday, becoming the youngest person to lead Northern Ireland. The timing will allow Arlene Foster, ousted as party leader in a putsch in April, to effectively bow out as first minister on Friday at a British-Irish Council meeting held in her home county, Fermanagh. Givan, who backed Poots to succeed Foster, said he faced a big responsibility in guiding the region through the coronavirus pandemic, economic recovery and health and education reforms. “We have a huge task when it comes to tackling our waiting lists and we need to get to work. So what we now need is an effective transition that needs to take place next week so we have that smooth delivery of governance.” In a break from precedent Poots decided to not take the job of first minister himself, leaving him to stay on as agriculture minister and focus on reorganising the DUP – a party riven in recent weeks by walkouts, resignations and accusations of bullying, sexism and intimidation, and blame for the post-Brexit Irish Sea border. The rancour which flared after Foster’s downfall and the failure of her ally Jeffrey Donaldson to win the leadership contest worsened after Poots announced his new ministerial team. He named Paul Frew as economy minister, Michelle McIlveen as education minister and several other DUP assembly members to other posts. The choices dismayed Foster’s old guard, who had hoped for an olive branch. “It is sad there is little sign of healing or reaching out,” tweeted Peter Weir, the outgoing education minister. The new team did not match rhetoric about uniting the DUP, said Diane Dodds, the outgoing economy minister. “Unionism can only grow if it is generous, inclusive and encourages as many pro-Union voters to the cause as possible.” Once Foster steps down as first minister so too must the deputy first minister, Michelle O’Neill, of Sinn Féin, starting a seven-day countdown to fill both posts. There is speculation Sinn Féin will demand a long-delayed Irish-language act – anathema to many unionists and loyalists – as the price of rebooting Stormont.