Sir Keir Starmer has appointed Tony Blair’s former chief of staff as his national security adviser.
Veteran diplomat Jonathan Powell will begin the role next month, it is understood, taking over from Sir Tim Barrow, who has held the role since September 2022.
Mr Powell, who was No 10 chief of staff between 1997 to 2007, played a key role in brokering the 1998 Good Friday peace deal in Northern Ireland.
The appointment comes at a crucial time, given conflicts in the Middle East and Ukraine, and Donald Trump’s return to the White House in January.
Sir Keir said Mr Powell’s experience made him “uniquely qualified” to advise ministers on global security challenges.
In his new role, Mr Powell will give national security advice to the prime minister and other cabinet ministers.
He will also act as secretary of the UK’s National Security Council (NSC), where ministers and intelligence chiefs discuss matters including foreign policy, defence, economic security, and resilience to security threats.
In April, previous prime minster Rishi Sunak announced that Major General Gwyn Jones, of the Royal Marines, would be replacing Sir Tim Barrow as national security adviser in the summer.
But Sir Keir cancelled the appointment on taking office and restarted the recruitment process, without offering an explanation.
A Conservative Party spokesperson said: “It is disappointing the government have appointed another Labour apparatchik to a senior role sidelining an experienced general.
“Mr Powell’s previous comments about the unimportance of British overseas territories are extremely concerning and many will be worried that there is more to come.”
Sir Keir brought Mr Powell in to lead negotiations over the recently-announced deal to cede sovereignty of the Chagos Islands to Mauritius.
The agreement, which ministers have said they want to ratify next year, will see the UK retain jurisdiction of the UK-US military base on the island of Diego Garcia for an “initial period” of 99 years.
The deal followed decades of often fractious negotiations between the UK and Mauritius over sovereignty of the archipelago, but has faced a backlash from several senior Conservative MPs.
A number of US Republicans have also attacked the deal, warning that it could help boost China’s influence in the region.
Mr Powell has dismissed Tory criticism of the agreement, insisting the UK’s decision to start negotiations in 2022 came amid a “very weak” legal position following international legal rulings that had sided with Mauritius.
He told Sky News that former Tory leadership candidate James Cleverly, one of those criticising the deal, had “enthusiastically” participated in the process when he was foreign secretary under Rishi Sunak.
After leaving Tony Blair’s Downing Street, Mr Powell led a UK-based charity working on international conflicts and was made UK envoy to Libya in 2014 under former Conservative prime minister David Cameron.
