Lynne Owens, head of the National Crime Agency (NCA), told police officers on rape cases to arrest first and investigate later while she was a chief constable.

Owens, tipped to be a future Metropolitan police commissioner, overhauled sex crime investigations to improve the detection rate when she was head of Surrey police.

However, her approach had a catastrophic effect, according to a Surrey man who said he was arrested for rape without an investigation that would have shown he was innocent. He said: It means anyone can turn up in a police station, make an allegation and you will be arrested.

Owens policy was revealed in the minutes of a meeting called in September 2015 by Kevin Hurley, who was then Surrey police and crime commissioner. The police force detection rate for rape and sexual offences was 12.9%, ranking it 38th nationally, Hurley pointed out. He asked Owens what she was doing to improve this.

The minutes record: The chief constable was keen to ensure officers were robustly pursuing offenders. Officers tended to receive an allegation then wait to make an arrest after gathering evidence. They needed to change this and make an arrest first and then gather the evidence.

Nick Ephgrave, then deputy chief constable, who now leads the force, told the meeting that arrest first had raised the rape detection rate from 6% to 15.8%, a significant turnaround in a year.

It is a particularly sensitive subject for the Surrey force, which was criticised after its officers appeared to accept Jimmy Saviles denial of sexual offences when they interviewed him in 2009. Owens, who is highly rated by Theresa May, took over as head of the NCA in January after four years as Surreys chief constable. Her overhaul of rape investigations is likely to reignite a debate over how to treat uncorroborated allegations of sex abuse.

The Sunday Times has spoken to a Surrey resident arrested last year after his former partner made two allegations of rape, which she said had taken place abroad in 2012.

The 49-year-old engineer said the arrest had a catastrophic effect on his life.

I spent four weeks on police bail, before being told there was no case. I thought all along Surrey were just arresting without investigation beforehand. There was not a shred of evidence in my case. Unless you have been in this situation you cannot believe the impact it has on your life. This approach is out of control.

Surrey police said the timing of an arrest was considered - on a case by case basis. Early arrests may be necessary in order to secure and preserve evidence. This evidence can include the suspects accounts in respect of the offence, or forensic evidence from the suspect or scene, or other evidence relating to the offence which could be interfered with or disposed of. In addition to this, the investigator would also take into account the risk posed by the alleged offender to the victim or other persons. Owens was not available for comment. But an NCA source said the minutes of the Surrey meeting were not necessarily exact quotations and the arrest first approach had to be seen in the context of how to raise the detection rate. Veteran investigators point out that, for years, trainee police officers were taught at college a mantra known as ABC: accept nothing, believe no one, check everything. After the Savile scandal and claims of a cover-up involving establishment paedophiles, police chiefs changed the policy in 2014 to the presumption that a victim should always be believed. However, the new guidance was blamed this year after the implosion of Operation Midland, which centred on paedophile allegations made by a single witness known as Nick. Sir Bernard Hogan-Howe, the Met commissioner, subsequently said his officers should stop believing every complaint that was made as it was not wise for any good investigator. David Tucker, head of crime and criminal justice at the College of Policing, said: Where you have, say, an historical allegation then you would have a different arrest strategy and would talk about gathering evidence.