An American Shakespeare scholar had his dreams of studying at Kingston University ruined when he was arrested and imprisoned for 10 days by immigration police, despite being in the UK legally.

Dr Paul Hamilton, 42, has lived in the country for nine years, but was arrested on January 17 at his home in Stratford-upon-Avon and taken to the Morton Hall Immigration Removal Centre near Lincoln.

The Californian was arrested even though his application for a visa extension was still being considered.

He had even purchased a return ticket to the United States in case his application was rejected.

He was released on Wednesday, but while detained the deadline for the research fellowship application he had worked on for months – which he hoped would land him a role at Kingston – expired.

Dr Hamilton said: “I worked on the application for months and tried my best to get it together [in prison] but I couldn’t have access to my research, and without that it just couldn’t be done.

“They call it detention, but I think that whitewashes what it actually is. It’s prison. You have bars, cells, barbed wire fences, all of the traits of prison.”

Dr Hamilton is also a central part of the Kingston Shakespeare Seminar, which aims to make the Rose Theatre a world centre for Shakespeare study and performance.

He said: “The guy who arrested me felt really bad about doing it. He even refused to process me and called his superior to ask: ‘Do we really want to do this? Is this really the sort of person we want to arrest?’

“The Home Office came back and said I was exactly the sort of person they wanted to arrest.”

Dr Hamilton had applied for leave to remain in the country under the 10 year route, meaning he had to prove he had friends or family in the UK.

His claim was branded “clearly unfounded” by the Home Office with no in-country right of appeal.

His flight back to the US has been booked for Monday.

New immigration rules announced by Home Secretary Theresa May mean non-EU migrants who have lived in the UK for five years must also prove they earn at least £35,000 – far more than Dr Hamilton takes home as an academic.

Dr Hamilton’s lawyer Theresa Okogwa said the Home Office had acted “disgracefully”.

She said: “He knew it would be difficult to get the extension because of rule changes, but we were never told his application had been refused. He wasn’t in the country illegally.”

A Home Office spokeswoman said: “Mr Hamilton’s application for indefinite leave to remain in the UK was refused on the grounds that he did not satisfy the relevant criteria.”

She added that he had the option of appealing against the decision after his departure.

Dr Hamilton said he will not appeal, having already spent almost £5,000 on visa and lawyer fees after his arrest.

Kingston Shakespeare Seminar has written an open letter about the arrest in support of Dr Hamilton.

It reads: “On behalf of Paul and his friends here at Kingston Shakespeare, a heartfelt thank you for the overwhelming support everyone has shown.

“Paul is lucky to have had so much support but there are many who are not in such a fortunate position. The story will not end here.”