Keir Starmer has appointed Antonia Romeo as cabinet secretary, the UK’s most senior civil servant, praising her drive and professionalism.

The appointment comes after high-profile criticism of Romeo from the former permanent secretary of the Foreign Office, Simon McDonald. Romeo has been highly praised by other previous secretaries of state, as well as the current home secretary, Shabana Mahmood.

Romeo, the longest serving permanent secretary in the civil service, has a reputation as a reformer and has been a more prominent public figure than many of her contemporaries.

She has previously faced accusations of bullying related to her time as consul-general in New York in 2017, but was cleared by the Cabinet Office.

She is the first woman to hold the post in the 110-year history of the role and has been a key figure behind the scenes in many government departments, including spells as permanent secretary at the Home Office, the Department for International Trade (which was set up from scratch post-Brexit ), and the Ministry of Justice, leading the official response to the 2024 summer riots.

She replaces Chris Wormald, who left last week after being widely seen as ineffective by senior figures in No 10. Romeo, who was mentored by one of the longest serving cabinet secretaries, Jeremy Heywood, was shortlisted for the top job when the previous cabinet secretary, Simon Case, left the civil service, but lost out in the final round to Wormald.

Starmer called her “an outstanding public servant, with a 25‑year record of delivering for the British people” and said he had been impressed by her professionalism and determination to get things done.

“Families across the country are still feeling the squeeze, and this government is focused on easing the cost of living, strengthening public services and restoring pride in our communities. It is essential we have a Cabinet Secretary who can support the government to make this happen,” he said.

“Antonia has shown she is the right person to drive the government to reform and I look forward to working with her to deliver this period of national renewal.”

Romeo said it was a “huge privilege” to become the head of the civil service. “The civil service is a great and remarkable institution, which I love,” she said. “We should be known for delivery, efficiency and innovation, working to implement the government’s agenda and meet the challenges the country faces.”

Lord McDonald had told the prime minister in a Channel 4 News interview after Romeo’s appointment that there should have been “more due diligence” before picking Romeo. “The due diligence needs to be thorough. If the candidate mentioned in the media is the one, in my view, the due diligence has some way still to go,” he said.

No 10 said full vetting had taken place when Romeo was shortlisted for the role after Case left. Downing Street said it had consulted the civil service commissioner, Gisela Stuart, who said the full process did not need to be re-run.

Stuart said: “Dame Antonia Romeo has an excellent track record in leadership positions across the civil service, including three permanent secretary roles in some of the most complex operational departments in government.”

No 10 said an enhanced due diligence process had also been undertaken by the permanent secretary of the Cabinet Office and the interim chief people officer.