FAMILY TIME: (From top) Diana Hennen; Prakash Chandra Roy (sitting) with (from left) nephew Mahtap and sons Bidhan, Sadhan and Subodh; (second left to right), Keith Roy with his mother, brother Philip and father

Did Dr Bidhan Chandra Roy, West Bengal’s iconic chief minister from 1948 until his death in 1962, have a mystery elder brother by the name of Sannyasi Charan Roy in England?

The experts in India are adamant he didn’t.

Back in England, though, a remarkable tale has emerged of how Charan, said to be the eldest of the five Roy siblings, arrived from India in 1900, followed nine years later by his youngest brother, Bidhan.

Bidhan returned in 1911 with an FRCS and an MRCP after enrolling at St Bartholomew’s Hospital in London. But Charan, who also qualified as a doctor but from Edinburgh and settled in Leicester, was nicknamed “Frankie” and married a local English girl called Constance Annie Scott in 1909.

He was called “the black doctor” but this changed to “the poor man’s doctor” after he overcame racial prejudice with his selfless service to patients in the slums of Leicester. He was killed in a car crash in Leicester in 1935. Charan and Constance had three sons, Philip, Keith and Theo, born in 1910, 1912 and 1915, respectively.

Keith, who worked for the Indian Civil Service in India, and Theo, who “did nothing”, married — but died without children. Philip, who also married a Leicester girl, Hilda Florence Cannon, worked as technical adviser to the Indian High Commission in London from 1947 until his death in 1971. Philip had two daughters, of whom the elder, Diana Roy, married an American, James Hennen, and has two sons, Jonathan, 29, and Christopher, 25.

In notes left for Diana, Hilda said that she had learnt from Philip that “of the two brothers, Bidhan was tall and incredibly handsome, while Charan was of smaller stature.”

“The Roys in England have died out and as I get older I find myself wanting to impart much more knowledge to my two sons as I am the last link,” admits Diana, who was encouraged to talk by The Telegraph.

Though brought up as impeccably English, Diana, who is 62 and has battled cancer, explains: “Probably I have the time and space now because of impeding mortality. I guess I am wanting to close a story, square the circle. I could let it be but there are forces beyond my control.”

But experts back in India have rubbished Diana’s detailed account. Whatever Charan was, he wasn’t Bidhan’s brother, they say.

“Bidhan Chandra Roy was born on July 1, 1882, at Bankipur in Patna, the youngest of five children of Prakash Chandra Roy, an excise inspector, and Aghorkamini Devi,” the records state.

It is less clear whether Bidhan had two brothers and two sisters or three brothers and one sister. One report has even suggested that he was “the fifth boy” born to his parents. Two of the brothers were Subodh and Sadhan — the latter’s daughter Renu Roy studied English at Newnham College, Cambridge, married fellow communist Nikhil Chakravartty, and had a son, Sumit, who edits Mainstream which his father had founded.

Sumit Chakravartty, who is based in Delhi, hasn’t heard of Sannyasi Charan Roy.

Neither has Dr B.C. Roy’s biographer, Nitish Sengupta, who told The Telegraph: “When I wrote the biography of Dr B.C. Roy, it was known for certain that he had two brothers elder to him — Subodh and Sadhan. All three of them went to England for higher education. Subodh became a barrister, Sadhan an electrical engineer and Bidhan a doctor. They had two sisters. We know for certain that there was no other brother, not to speak of any Sannyasi Charan Roy.”

Sengupta adds that several other young men stayed at Bidhan’s parents’ residence and were educated by them. “It is possible that one of them may have been Sannyasi Charan Roy. He was certainly not Bidhan’s own brother nor does it seem possible that he could have been cut out by his adopted family back in India for marrying an Englishwoman. Bidhan’s parents were much too modern in their outlook.”

And that ought to be that — except that every bit of information Diana has provided, barring the moot point of whether Charan and Bidhan were brothers, have checked out against official UK census and medical records.

“Our archivist can confirm that Bidhan Chandra Roy became a Fellow of the Royal College of Surgeons of England on 8 June 1911,” The Telegraph learnt from the Royal College of Surgeons. “There is an entry in the Medical Register — Sannyasi Charan Roy at Laurel Villas, East Park Road, Leicester. It states: Date of Registration 26 November 1902 (Scotland) MB, CM, 1902, University of Edinburgh.”

Pamela Forde, archivist at the Royal College of Physicians, identified listings for Charan in the Medical Directory for 1910 and 1911, while Edinburgh University says Charan gave his Calcutta address as “Garden Retreat”.

There is a record of Charan’s marriage to Constance in 1909; and the 1911 census reveals he was born in India in 1875 and resident in Leicester.

Diana’s response to having cold water poured on her detailed account is: “It was just a given that my grandfather was the eldest brother of Bidhan. Renu was referred to as the red-hot communist cousin of my father.”

When Philip and Hilda married in 1947, Bidhan’s wedding gift was a silver framed photograph of himself, says Diana.

As a schoolgirl, Diana and her parents visited Keith in Mumbai in 1954, 1961 and 1964 but there was no contact with Bidhan in Calcutta. Diana has not been back to India for 46 years but is telling her sons as much as possible about their Indian heritage, starting with Charan Roy’s arrival in 1900: “If something happens to me, ‘Here’s the story, boys.’ ”

A DNA test would establish whether Diana has any relatives in India but maybe this is a case where Sherlock Holmes and Feluda ought to put their heads together.