POLICE strategy on the Aberdeenshire golf resort being built by US tycoon Donald Trump was targeted against protesters – but that was a mistake, according to an internal police report obtained by the Sunday Herald.

Grampian Police said that due to an “admin error” it had recorded that its aim was to “deter, detect, detain and report those responsible for unlawful protest” against the controversial development. It should have said “unlawful behaviour”.

A handwritten note in a police file released under freedom of information legislation warned this could lead to accusations that the police were biased in favour of Trump. “Emphasis on ‘protest’ could be seen as an imbalance in terms of neutrality,” it said. “‘Behaviour’ is more appropriate and was original strategy.”

The revelation has resurrected claims that Grampian Police acted as Trump’s private security force in protecting the billionaire’s £750 million golf course and hotel complex on the Menie Estate. Last year, two documentary filmmakers were arrested and detained after interviewing a member of Trump’s staff, but breach of the peace charges against them were then dropped.

The file also reveals that reports earlier this year that Trump might run for US president created anxiety within Grampian Police. This could have a “potential significant impact on local policing deployment,” said one note, and the Metropolitan Police in London and US intelligence agencies were asked for advice.

Anthony Baxter, one of the filmmakers arrested in July last year, described as “deeply troubling” the suggestion that protesters should be detained. “Grampian Police should know that there’s nothing unlawful about the legitimate right to protest over the destruction of one of Britain’s last remaining wilderness areas,” he said.

He added residents and campaigners had “long complained about being branded ‘protesters’ and ‘parasites’ by the Trump Organisation – a view they feel has been echoed by the behaviour of the police.”

Baxter’s award-winning film, You’ve Been Trumped, is due to screen again at Edinburgh Filmhouse from November 18.

Local resident David Milne, who opposes Trump’s development, said there was a “huge and significant difference” between unlawful protest and unlawful behaviour.

A Trump Organisation spokeswoman described the criticisms of the police as “irresponsible and unjustified”. She added: “We have been subject to numerous acts of vandalism and were quite within our rights to call for police intervention.”

The Green MSP, Patrick Harvie, said. “Grampian Police appear to have decided in advance that peaceful protesters are criminals, but to ignore the bullying and vandalism perpetrated by Trump and his associates. This is yet another worrying instalment in this sorry saga.”

Grampian Police declined to comment.