A copy of Lady Chatterley’s Lover used by a judge at the book’s landmark 1960 obscenity trial, with all the rude bits carefully and dutifully marked up by his wife, has been temporarily stopped from leaving the UK.

The arts minister, Michael Ellis, has placed an export bar on a copy of the DH Lawrence novel taken in to court by Sir Laurence Byrne. The government now hopes a UK-based buyer will be able to match the £56,250 asking price.

The decision was made on the advice of a committee of experts chaired by Sir Hayden Phillips, who said the copy was a “witness” to one of the most important criminal trials of the 20th century.

Phillips asked people to picture the scene: “The high court judge presiding in his red robes, his wife beside him on the bench (as was allowed in those days) as a succession of singular and distinguished witnesses for the defence were cross examined day by day.

“I was 17 at the time and studying DH Lawrence as a set text for A-levels – it was not Lady Chatterley’s Lover, but at least I could follow the riveting course of the trial in the daily papers. It would be more than sad, it would be a misfortune, if this last surviving ‘witness’ left our shores.”

Lady Chatterley’s Lover was Lawrence’s final novel before his death in 1930 and tells the story of an aristocratic wife trapped in a sexless marriage, finding passion with a handsome, lusty gamekeeper. It was not published in full in Britain until 1960 because of fear of prosecution.

The trial at the Old Bailey, a test case for the 1959 Obscene Publications Act, was a sensation, a clash between the out-of-touch establishment and the permissive society of the 60s.

The opening remarks of the lead prosecutor, Mervyn Griffith-Jones, spoke volumes: “Would you approve of your young sons, young daughters – because girls can read as well as boys – reading this book?

“Is it a book that you would have lying around in your own house? Is it a book that you would even wish your wife or your servants to read?”

Clearly one wife who had read it, meticulously and assiduously, was Lady Dorothy Byrne, who underlined the racier bits and wrote a separate list of significant passages – “more love making”, “coarse” etc – with page numbers. She even hand-stitched a damask bag for her husband to take it, discreetly, in to court.

A queue for admission to the Old Bailey’s public gallery during the 1960 obscenity trial over Lady Chatterley’s Lover. Photograph: AP

It took just three hours for the jury to decide that the book did not deprave and corrupt, helping to redefine British attitudes to sex.

Byrne’s summing-up was seen as fair, but his private feelings were perhaps given away when he refused to award costs to the book’s publishers, Penguin.

Not that they would mind too much. Penguin’s print run of 200,000 sold out within a day. Within two years, 2m copies had been sold to a public eager to read passages such as: “She lay still, feeling his motion within her, his deep-sunk intentness, the sudden quiver of him at the springing of his seed, then the slow-subsiding thrust.”

The copy found its way in to the large and idiosyncratic collection of a reclusive billionaire, Stanley J Seeger, and his partner Christopher Cone. Since Seeger’s death in 2011, Sotheby’s has held a number of sales of his possessions, with eclectic objects including Al Capone’s cocktail shaker – inscribed “To a ‘regular guy’ from the boys 1932” – to Marilyn Monroe’s picnic basket.

The book was sold to an overseas buyer last year for £56,250 and the export bar offers a window for a UK organisation or individual to match that.

Ellis said: “The trial of Lady Chatterley’s Lover captured the public attention in 1960. It was a watershed moment in cultural history, when Victorian ideals were overtaken by a more modern attitude. I hope that a buyer can be found to keep this important part of our nation’s history in the UK.”