The Home Office has relaunched the process to find the next National Crime Agency director general amid accusations of cronyism.
The department has readvertised the £223,000-per-year job after rejecting candidates chosen by an expert panel.
No.10 reportedly asked for a rerun after Boris Johnson's pick, former Met Police commissioner Bernard Hogan-Howe, failed to reach the final two.
A panel which oversaw the initial selection process had picked out Met assistant commissioner Neil Basu and NCA acting DG Graeme Biggar as their preferred candidates for the role, according to reports.
But Home Office permanent secretary Matthew Rycroft told the duo last month they would not be chosen and the process would be rerun, the Guardian said.
The process is believed to have been halted because Lord Hogan-Howe, one of the final four candidates for the role, did not reach the final two, according to the Sunday Times.
Basu, who is the former head of UK counter-terrorism policing, told the newspaper he was “disappointed in the way the process has concluded” and would not apply again.
“I will be seeking an explanation from the Home Office,” he added.
If he had been appointed, Basu would have become the first person of Asian heritage to lead a UK law enforcement organisation.
Basu, Hogan-Howe, Biggar and two others were interviewed by an expert panel of five people, including Rycroft, MI5 DG Ken McCallum and Home Office non-executive director Michael Fuller, who is the only black Briton to ever reach the rank of chief constable.
Hogan-Howe, who was Met Police commissioner during Johnson’s tenure as mayor of London publicly endorsed Johnson’s bid for the Tory leadership in 2019, saying: “I found him to be loyal, honourable and he did what he promised to do.”
He has refused to rule himself out of the race and said he is “proud” of his record as Met commissioner from 2011-2017.
The NCA’s previous chief, Dame Lynne Owens, retired in September 2021, with Biggar appointed as the agency’s interim DG from October.
The recruitment process for the DG role is unregulated and does not have to be conducted according to civil service or public appointments rules, with ministers able to re-run the process and no requirement for the government to publish details of how a decision is made.
There is also no duty on the government to advertise the role publicly, although in this case both the initial and the latest adverts have been published on the Civil Service Jobs website.
Institute for Government researcher Grant Dalton said such an important and high-profile role “should not rest on the judgement of ministers alone, without any opportunity for scrutiny”.
He said the position should instead be regulated, either by the commissioner for public appointments “or preferably by the first civil service commissioner”.
Repeated recommendations that all ministerial appointments should be regulated have been rejected, including most recently the Grimstone review in 2016.
A series of recent unregulated appointments have been criticised in recent years, including the 'unlawful' appointment of Dido Harding as head of NHS Test and Trace and then-health secretary Matt Hancock's lover Gina Coladangelo being apppointed to the board of the Department of Health and Social Care.
A Government spokesperson, said: “A fair and open recruitment campaign is underway to make the best possible appointment to this vital role.
"Recent events have demonstrated how pivotal the NCA is in protecting the public from organised crime and national security threats. This process will ensure that the home secretary is able to appoint the best possible candidate as the new director general, with the leadership skills and experience to take this vital work forward.”