AN academic who passionately supported Police Scotland’s stop and search policy has been accused of making an “astonishing u-turn” by co-authoring a book that criticises the controversial tactic.

Professor Ross Deuchar, who was a Fulbright scholar and is based at the University of the West of Scotland, previously claimed that the application of stop and search had been an “overwhelming success” – and even allowed the force to edit one of his speeches.

However, after the policy collapsed amid political, academic and political scrutiny, Deuchar has written that stop and search is part of a “culture of control” of young people.

Professor David Miller, a professor of sociology at Bath University, said: “This is an astonishing u-turn. If research shows that previous views are wrong, then any new view should be accompanied by an explicit recognition of the change and the evidence underlying it.”

In 2014, it emerged that Police Scotland had recorded over 500,000 frisks between April and December 2013, but the figure was questioned after police sources said that officers had falsely recorded searches due to the pressure of trying to meet targets.

In another blow for the policy, it was revealed that a majority of the procedures were “consensual” or "non-statutory searches", meaning they were undertaken with no reasonable suspicion that illicit items were being carried.

Reforms led to “consensual” searches being phased out and the total number of frisks tumbled by over 90 per cent.

In a new book, Young People and Social Control, Deuchar and his co-author focus on the “views and perceptions” of young people living at the margins of society.

Some sections focus on stop and search and include negative comments from young people who had first-hand experience of the policy.

In one passage, the authors state that the young men who participated in interviews felt their experiences with officers were “procedurally unjust” and some talked about being threatened with full body strip searches.

The authors write: “We argue that the use of stop and search is one disciplinary mechanism that provides a powerful arm for this culture of control.”

They added: “They [the young men] continued to feel unfairly and unjustifiably stopped and searched and believed that the encounters themselves were authoritarian, disrespectful and stigmatising.”

However, three years ago, Deuchar, was a high-profile supporter of stop and search in Scotland.

In a newspaper article in January 2014 he wrote that the “interventions I observed were always based on intelligence, and were invariably positive”.

He added: “My experiences have shown me that officers are drawing upon the fundamental values of integrity, fairness and respect in conducting stop and searches, and winning the trust of many young people along the way..”

His article was published days before another academic, Dr Kath Murray, published groundbreaking research into stop and search that led to the policy unravelling.

As previously revealed by the Sunday Herald, Deuchar had liaised with Police Scotland about his newspaper article. In one email, he wrote: “I will crack on and get something written and run it by you over the weekend or on Monday.”

He also wrote a positive tweet about “consensual” searches: “More than 70 per cent of stop searches over the last year have been consensual. A terrific example of values-based policing.”

At a public debate in Glasgow later in that year, Deuchar argued against putting stop and search on a statutory footing and in favour of “consensual” frisks.

Emails revealed that Professor Deuchar had sent the force a draft copy of his speech and allowed changes to be made. In his speech, he claimed that the “constructive application of the tactic has been and continues to be an overwhelming success”.

Speaking about his time observing searches he said he had been “surprised and delighted” to discover the “extremely positive impact” that the procedures had on “fostering positive, trustful relationships”.

In a statement to this newspaper, Professor Deuchar said: “The contents of this new book are based on insights from very recent, robust research conducted with young people. The book illuminates young people’s described personal experiences with agents of social control, including their experiences with police officers. The latter includes - but is not confined to – their experiences of stop and search.

“Although many negative views about stop and search were articulated during the interviews conducted with young people, there are also some positive illustrations of young people’s experiences with police officers recorded in the book. The chapter on policing is based on recent funded research that led to much wider empirical data than my previous work in this area and as a result of this study my views are naturally more informed on the issue of stop and search and the wider issues relating to youth/police relationships.

“In the book there are many references to my previous published academic work on policing and on police/youth relationships, all of which provide objective insights and illuminate both positive and negative illustrations of practice."