A diamond ring going up for auction next month at a Pontrilas sale room could lift the lid on one of the greatest literary scandals of the Victorian age, and confirm strongly denied rumours that author Charles Dickens had an affair with his sister in law, could in fact be true.

In his lifetime, Dickens described the widespread rumours as 'most grossly false, most monstrous and most cruel' but the history of the diamond ring - a gift from poet Alfred Lord Tennyson - seems to indicate that Dickens and his sister-in-law Georgina Hogarth did in fact have a son.

Georgina, sister of the author's wife Catherine, with whom he had ten legitimate children before their separation in 1858, lived in their family home as a housekeeper from the early 1840s until the author's death in 1870 and the relationship soon became the subject of society gossip.

So quickly did this spread that Dickens issued a statement to The Times and other newspapers saying that 'all the lately whispered rumours touching the trouble at which I have glanced, are abominably false'.

After one particularly scurrilous report that Georgina had borne him three children Dickens, worried that the scandal could lead to a costly divorce and a criminal conviction - as a relationship with a sister in law was treated as incest -insisted that a doctor should examine Georgina and attest to her virginity.

Despite this, following his death, his will revealed that he had left Georgina far more than his mistress and his wife - most of his jewellery and the vast sum of £8,000 - describing her as his most trusted friend.

Despite his highly moral writings, Dickens is believed to have fathered several illegitimate children during his lifetime, and it is now widely accepted that he had a longstanding affair with an 18 year old actress, Ellen Ternan, during his marriage and both she and Georgina were at his bedside when he died in 1970 at the age of 58.

It has long been understood by the owners of the ring, which is expected to fetch in the region of £25,000 - £30,000 when it is auctioned by Nigel Ward and Co at its Pontrilas auction room next month, that it was acquired by their ancestor Hector Charles Bulwer Lytton Dickens, who claimed throughout his lifetime that he was the son of Charles Dickens.

According to letters and other documents the ring was bought by Hector Dickens from his 'step brother' Alfred D'Orsay Tennyson Dickens, who had been given the ring by his father before he had left England bound for Australia.

This is supported by a letter written by Hector in 1924 in which he lists his valuables and refers to a ' Large Diamond Ring belonging to my father bought by me from my brother A.T. Dickens in Melbourne in 1890. Engraved inside 'Alfred Tennyson to Charles Dickens 1854', the year of my birth."

Hector Dickens, who was often known during his lifetime as Charles Dickens the Younger, died in 1932 and bequeathed the ring to Lily Susan Hale, the niece of his late wife Edith, with whom he lodged, firstly in Twickenham and later in Bournemouth.

Miss Hale gave the ring during her lifetime to John Dorrington Dickens Bennett, her nephew and the godson of Hector Charles Bulwer Lytton Dickens.

During his lifetime he gave the ring to his sister, for whom the ring is now being sold.

"It has long been the understanding of the owners of the ring that Hector (pictured right) was the illegitimate son of Charles and Georgina Hogarth and having looked at the documentation I believe that this is right," said auctioneer Nigel Ward.

Mr Ward explained that the owners of the ring, who have local contacts, had contacted him after reading reports of an antique atlas which recently sold at his Pontrilas sale room for £38,000

"They felt they would rather sell the ring locally than have to travel to London and take a potentially very valuable item across the city," he said.

Mr Ward admitted that he initially approached the ring with some caution, but has since become convinced that the family's story is right.

"We've had the ring checked at the Assay Office and they say that the gold and the diamond fits exactly with the period and that the wear on the inscription is consistent with the wear it would have had," he said.

"The documents, which include wills and newspaper stories describing Hector as the son of Charles Dickens are also very convincing.

"These rumours dogged Dickens in his lifetime and it seems as if the ring is about to confirm that he did have an illegitimate child with his sister in law."

Mr Ward added that he hoped that the new information could prompt other families to come forward with further revelations about the author.

"So often families have information they keep secret for various reasons, until something like this makes them change their minds," he said.

With around a month to go before the auction, it's hoped that further information may come to light to place the ring firmly in the possession of the Dickens family.

"I have seen some pictures of a portrait of Charles Dickens painted in 1855 and which is now at The National Portrait Gallery in London in which he appears to be wearing the ring on the little finger of his right hand," said Mr Ward.

"I am still waiting to see a higher resolution version of the portrait to confirm this, but if it is the ring it could make a huge difference."

"We are anticipating that the ring will make in the region of £25,000 - £30,000 but a desk and chair owned by Dickens was sold last year in a charity auction for £433,250 so who knows.

"If it sells for £30,000 I'm sure the family will be delighted, but if it sells for £300,000 I don't think they'd be unhappy," he added.

Some historians are less than convinced by the claims that Dickens fathered an illegitimate child and one, Clair Tomalin, who wrote a biography of his mistress Ellen Ternan claimed that Hector was an Australian conman called Charly Peters, who used the rumours of Dickens' infidelity to trick people out of money.

"I've spoken to a number of experts and they were initially sceptical but they do seem to be coming around to the thinking that this could be a genuine claim," said Mr Ward.

"Hopefully further research will prove this," he said.

Commenting on the find, Florian Schweizer curator of The Dickens Museum in London, said, "There have been rumours of them having an affair but it has never been substantiated because there has never been any reliable evidence to emerge.

"They lived together for the last 13 years with Georgina as a friend and companion, but Dickens also had a mistress at the same time.

"There was a lot of gossip and it never really left the public imagination as a juicy tale of something of his private life.

"I have seen a picture of the ring and the documents. It would turn the Dickens' scholarship of the last 80 or 90 years on its head if it was true.

"But even if we accept the provenance of the ring, it still does not categorically confirm the two had an affair or that Hector was, in fact, the illegitimate love child."