A probe by His Majesty's Inspectorate of Constabulary in Scotland (HMICS) also revealed the force does not re-vet employees who hold only recruitment vetting.

The force is now being advised to undertake an urgent review to ensure all workers have been subject to at least recruitment vetting.

The police watchdog is also calling for those who hold only recruitment vetting to be re-vetted every 10 years.

Deputy Chief Constable Alan Speirs said the safeguarding of the force's values and standards "has never been stronger".

Earlier this year, Police Scotland announced all 22,000 staff would be checked against national databases amid a pledge to step up vetting following the case of David Carrick.

Former Met Police officer Carrick was handed 36 life sentences in February after admitting dozens of rape and sex offences while serving on the London force.

Carrick's conviction followed that of Met officer Wayne Couzens, who was handed a whole-life order for the murder of Sarah Everard.

Ms Everard was kidnapped, raped and murdered after Couzens staged a fake arrest.

That process is still under way, however. In the HMICS report published on Tuesday, the watchdog highlighted there is no legal requirement for the force to vet officers and staff.

It also noted that training and mentoring within the Force Vetting Unit (FVU) is of a "high standard".

However, in its key findings, it reported several gaps in the system.

They include:

• There was no check or review of vetting clearances held by officers and staff employed by legacy forces on the creation of Police Scotland in April 2013.
• Not all serving police officers and staff have a vetting record held on Core-Vet (the force's vetting system).
• Police Scotland does not re-vet officers or staff who hold only recruitment vetting.
• The force has no easily identifiable requirement for officers or staff to notify the organisation of any off-duty criminal conviction, offence or charge.
• It does not have a process for reviewing vetting clearance following misconduct.
• The force does not withdraw or suspend recruitment vetting.

HMICS is now calling for the Scottish government to introduce legislation that would allow the chief constable to "dispense with the service of an officer or staff member who cannot maintain suitable vetting".

Among the 15 recommendations, the watchdog is also calling for an "annual integrity review" and policies should allow all levels of vetting clearance to be "refused, suspended or withdrawn".

Designated posts should be reviewed "as a matter of urgency", according to the report, with priority given to posts that require working with vulnerable people.

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In response to the HMICS report, Mr Speirs said: "The safeguarding of our values and standards has never been stronger and HMICS rightly highlights the high standards of our vetting.

"Over 5,000 officers and staff are vetted to an enhanced level with annual reviews and we will ensure all roles have the right clearance levels.

"We've invested to enable additional checks for new recruits before they are sworn into office and, working with staff associations and unions, we are introducing a programme of re-vetting.

"We know the onus is on us to earn public confidence and will carefully review this report to identify any further improvements which can strengthen our vetting."