Boris Johnson ally David Frost to become UK national security adviser

David Frost is Britain’s chief negotiator with the EU and will replace Mark Sedwill

David Frost, Britain’s incoming national security adviser. Reuters

One of Boris Johnson’s closest political friends has been appointed the UK’s next national security adviser.

David Frost is taking over from Mark Sedwill, Britain’s most senior civil servant, who announced on Sunday he was resigning as national security adviser and Cabinet secretary.

Mr Frost, who is Britain’s chief negotiator with the EU, will replace Mr Sedwill as national security adviser in late August.

The civil service has lost a number of its leaders since Boris Johnson’s Conservative Party won last December’s general election, and Dominic Cummings became an adviser to the prime minister.

Mr Cummings, who faced calls for his own resignation after he drove from London to Durham in northern England during lockdown, wants major changes to the civil service.

Mr Frost is close to him and his appointment could be a sign that Mr Cummings remains influential in Mr Johnson's administration, ITN reported.

“I look forward to helping deliver the prime minister’s vision for a global Britain, with real influence around the world,” Mr Frost said.

He will remain chief negotiator for the rest of the Brexit talks.

Britain is still hammering out its final deal with the EU as the end-of-year deadline approaches.

Some believe it could eventually leave without any agreement being reached.

Mr Johnson said he was confident Mr Frost would make a “difference to this country’s ability to project influence for the better”.

Mr Frost has extensive experience in diplomacy, including a stint as ambassador to Denmark and at the Foreign Office, where he has previously worked with Mr Johnson.

Politics Home reported Mr Frost had also joined the advisory council of Open Europe, a British centre-right Eurosceptic policy think tank, during a spell away from the civil service.