An investigation has been launched into allegations that one of Scotland’s senior planning officers has breached her professional code of conduct by “colluding” with US property tycoon Donald Trump.

The Royal Town Planning Institute (RTPI), which represents 22,000 planning officials in the UK, is examining a complaint that Dr Christine Gore, director of planning for Aberdeenshire Council, failed to act with integrity and independence while handling Mr Trump’s application for a £1 billion luxury golf resort.

The council has defended Dr Gore and promised full co-operation with any investigation. It accused Mr Trump’s critics of promoting “misinformation” to win publicity for their cause.

The investigation comes as a new opinion poll released today shows that three-quarters of Scots are opposed to any plans Mr Trump might have to use compulsory purchase to evict families from their homes to make way for his luxury leisure and housing development. This contrasts with claims by Mr Trump that he has strong local support for his scheme.

The plans for two championship golf courses, 950 holiday homes, 500 luxury homes and a 450-bed hotel were narrowly rejected by an Aberdeenshire Council committee in 2007. Council leaders tried to reverse the decision, but the application was called in by the Scottish Government, and later approved after a public inquiry.

The complaint against Dr Gore has been made by a former member of the RTPI, Bob Marshall from Glasgow. He alleges Dr Gore brought her profession into disrepute by not informing homeowners they were facing eviction and by appearing to side with Mr Trump.

Mr Trump’s lawyer, Ann Faulds, drafted a four-page report, for submission to councillors, in Dr Gore’s name justifying the evictions, though it was never used. An email from Dr Gore to Ms Faulds in April requested at least a week’s notice of Mr Trump’s application to help manage media interest.

Thereafter “close liaison” would be required, Dr Gore wrote, “in order that we can have a managed approach to what is inevitably going to be a difficult and emotive reaction given that this new application will involve land outwith the applicant’s ownership”.

Mr Marshall alleges Dr Gore “appears to have colluded with the developer’s solicitor”, and argues that her use of the word “emotive” was pejorative.

Aberdeenshire Council, however, insisted its officers had always acted with integrity and independence in an extremely complex and controversial planning application.

A spokesman stressed that the council had tried to be as open as possible about its handling of Mr Trump’s application. Dr Gore had no control over what documents were sent to her, and the draft report to councillors on evictions had been “unsolicited”.

The RTPI declined to comment on the case.

The Tripping Up Trump campaign group accused Aberdeenshire Council of “secretly pampering” Trump while turning their backs on homeowners. Last month the council refused to rule out evicting people to make way for Mr Trump’s development. Four families are potentially at risk.

The anti-Trump group, along with the Scottish Green Party, commissioned a poll last month asking Scots if they supported evicting local residents to accommodate the Trump development. Only 13% said they backed the move, with an overwhelming 74% opposed.

Liberal Democrat voters were most opposed to the idea, by 86% to 7%, followed by SNP voters, by 73% to 14%. Aberdeenshire Council is controlled by a coalition of LibDem and Conservative councillors.

Green MSP Patrick Harvie said: “The administration on Aberdeenshire Council should be ashamed of itself for not having stood up for local residents before now, but perhaps the prospect of a public revolt will change their mind.

Mr Harvie also argued that it was now increasingly unlikely that Mr Trump’s golf resort, which he described as a “gated community for the rich” would ever be built.

Trump International Golf Links Scotland did not respond to a request for comments.