While based at Moradabad in 1888, he successfully operated on Muhammad Mushtaq Ali Khan, the Nawab of Rampur, crushing his bladder stone with a lithotrite.

This and an eye injury caused while serving the civil surgeoncy of Benares contributed to Freyer taking early retirement and returning to England in 1896.

In England he set up a private practice in Harley Street and was appointed a consulting surgeon in the surgery of the urinary organs at St Peter's Hospital for stone, London.

In 1920, he was elected the first president of the section of urology of the Royal Society of Medicine and in his presidential address, claimed to have performed 1,674 of these operations with a low mortality.

[1] Freyer and his siblings however, were brought up as Protestant, a likely effect of the influence of the Irish Church Missionss (ICM) on the people in the area at that time.

[8][9][10] In 1888,[11] while based at Moradabad, Freyer operated on the Nawab of Rampur, Muhammad Mushtaq Ali Khan,[12] crushing his bladder stone with a lithotrite.

[5][13][14] In 1894, Freyer represented the Indian government at the International Medical and Surgical Congress in Rome, where he presented his study on 598 cases of bladder stone removal by transurethral lithopaxy, using the same technique as Henry Jacob Bigelow.

[5][15] His troubles with his superiors in India and an eye injury from an assault by a patient at the Benares asylum contributed to Freyer taking early retirement in 1896 and he returned to England.

He described Freyer in a letter to his brother, as a "brusque, blunt, rather aggressive man in manner...He seems to have rather a high opinion of himself and I certainly thought him a skilful operator".

He continued in his letter that Freyer "showed me his large collection of prostates, over a hundred in all" and pointed out a number from notable men including one from Lord Kelvin.

[23] The number of articles and lectures Freyer gave, in addition to the publicity surrounding the controversies regarding his claims that he had introduced the operation, likely helped make the procedure widely known.

[9][21][22] In addition to the scandal in India caused by receiving fees from the Nawab, being accepted into the London's medical circles was not likely helped by being Irish.

[25] John Thomson-Walker, first honorary secretary of the section of urology at the RSM,[26] later described Freyer's surgery as "decided, purposive and rapid, and in some operations, especially that of litholapaxy, the manipulation was graceful".

[5] When Cuthbert Dukes became president of the urology section of the RSM in 1956, he disclosed that when he took up the appointment of pathologist at St Peters 26 years previously, he had come to be in possession of the medical notes and pathological specimen of the prostate removed from Freyer's first transvesical prostatectomy case of John Thomas in 1900.

[27] In 1902, he became examiner in surgery at the University of Durham and from 1904 to 1909 he was a member of the honorary medical staff of King Edward VII's Hospital for Officers.

[3] Freyer was seen to be a "staunch Home Ruler", and the papers held at the NUI, Galway, provide evidence that he was friends with the Redmond brothers, William and John, who he operated on in March 1918.

[9] Every year, the Sir Peter Freyer Memorial Lecture and Surgical Symposium, established in 1975 by professor O'Beirn, is hosted by the Department of Surgery, NUI Galway.

[3] Past lecturers have included Peter Froggatt in 1984, Thomas E. Starzl in 1985, Mutsuo Sugiura in 1986, Thomas J. Fogarty in 1987, Bernard Fisher (scientist) in 1988, Norman Stanley Williams in 1989, Geoffrey Duncan Chisholm in 1991, Patrick J. Kelly in 2001, Ara Darzi in 2002, Steven D. Wexner in 2004, Peter T. Scardino in 2006 and Patrick Gullane in 2009.

Subsequently, in 2002, the James Hardiman Library at the NUI acquired them and now hold around 660 items consisting of his letters, newspaper cuttings, official records, photographs, memorabilia and publications.