ALLEGATIONS of corruption and criticisms of senior officers were removed from an internal report into the early days of Police Scotland, according to a BBC investigation.

The report was commissioned by the former chief constable Sir Stephen House in 2014, a year after the single national force began.

It followed concerns that bad practice and unlawful behaviour within some legacy forces had carried on into Police Scotland.

A BBC Scotland investigation claims drafts of the report show the chief constable's office wanted negative comments deleted, tenses changed to suggest problems had been fixed, and an entire section, where frontline officers described working in a culture of fear, removed.

The investigation, A Force In Crisis, is to be broadcast on Monday evening.

It is claimed early drafts of the report detailed officers conducting unauthorised surveillance, threatening and intimidating witnesses, unlawfully detaining suspects, colluding whilst compiling statements and failing to reveal evidence, but were removed from the final version.

The BBC investigation said more than 300 officers were questioned for the report, titled Police Scotland Quality Assurance Review, with many criticising performance targets and the force's leadership in early drafts.

Police Scotland said "significant changes" have been implemented in the four years since the report and that Iain Livingstone, the current interim Chief Constable, has "already acknowledged that in the early days of Police Scotland process was put ahead of people".

The Met Police, where Sir Stephen is now an assistant commissioner, said he was not commenting on the report.

Moi Ali, who resigned from the Scottish Police Authority (SPA) board last year after a row over transparency at the watchdog, told the BBC programme: "I am shocked that the chief constable's office should see fit to try to pretty much obliterate any kind of criticism whatsoever, because if this is what the report found, then this is what it found, and this is what should have been published."

A Police Scotland spokeswoman said: "The report was compiled four years ago and significant changes have been implemented since then.

"We have conducted several internal surveys and last year DCC Iain Livingstone, the interim Chief Constable, led the development of and launched a wellbeing strategy for all officers and staff.

"DCC Livingstone has already acknowledged that in the early days of Police Scotland process was put ahead of people at a time of challenge and difficulty for everyone involved.

"The service has been the focus of numerous external reviews and unprecedented levels of public scrutiny since 2014 and is committed to investing in our people as we build the organisation going forward."

An SPA spokeswoman said: "Five years on from the creation of Police Scotland, our focus is on the issues facing policing in 2018.

"That includes building a strong leadership team and positive organisational culture, including through the SPA's current recruitment campaign for senior officers."