Young history academics are too eager to convert their research into books that have only a slim chance of success in an increasingly crowded market, according to the chief judge of a leading history writing prize.

Sir Keith Thomas, the Oxford historian who is chairman of the judging panel for the Wolfson History Prize, applauded the growth of interest which has seen telegenic dons propelled on to the nation's television screens and bookshop shelves, but warned that the dash for the bestseller lists risks undermining the status of academic study.

Two women historians were last night named as this year's winners of the prize, which was founded 40 years ago to reward high-quality history writing that is accessible to the general public. Previous winners include some of Britain's most renowned historians, including Simon Schama, Eric Hobsbawm and Antonia Fraser.

But while the growth in genealogy and an apparently insatiable appetite for works on the grim events of the 20th century, from the Second World War to the Stalinist purges, has made history into one of publishing's star sectors, the profession's guardians are concerned that the pressure to achieve a public profile is damaging for academia.

In the past decade, sales of history books have increased by more than 45 per cent to nearly 5.4 million copies a year – more than double the rate of growth across the publishing industry as a whole, according to the publishing data company, Nielsen BookScan.

Sir Keith, who was a winner of the Wolfson History Prize in its first year, said: "There is a tendency for young historians who have completed their doctoral thesis to, rather than present it in a conventional academic form, immediately hire an agent, cut out the footnotes, jazz it all up a bit and try to produce a historical bestseller from what would have otherwise been a perfectly good academic work. The reality is that only a few of these works succeed commercially." The leading authority on the early-modern era said there was an increasing risk of a "parasitic" relationship between higher-profile historians with a flair for language and a publisher, and less eye-catching academics whose diligent efforts in archives and libraries end up being cited in the books of their more media-savvy colleagues.

"We now read in excess of 150 books a year, and a good number are neither one thing nor the other – they are not popular enough to gain a wide readership but neither are they sufficiently academic to interest many historians."

The list of 85 authors awarded the prize since 1972 would seem to prove the Wolfson judges' concern that their deliberately low-key award should not reward "popularity for popularity's sake" but instead seek out historical gems that command the simultaneous interest of "professional scholars and the intelligent reading public".

Earlier winners include texts that have become cornerstones of idiosyncratic modern historical writing, such as Theodore Zeldin's France 1848-1945, and global best-sellers, such as Stalingrad by Antony Beevor. This year's winners reflect a similar diversity of backgrounds. Susie Harries, who won for her biography of the architecture historian Sir Nikolaus Pevsner, has co-authored several books with her husband and writes on the arts in the 20th Century.

Professor Alexandra Walsham, who won for her book on the effects of the Reformation on the British landscape, in 2010 became the first woman hold the modern history chair at Cambridge University. Each receives £25,000.

The old school...

Eric Hobsbawm

The doyen of British historians, his avowed Marxism has gone hand in hand with recognition as one of the great analysts of the shaping of the 20th century. The 94-year-old is also a jazz critic.

Richard Overy

Apart from occasional TV and newspaper appearances, Overy largely moves within historical circles. In the 1980s, he was involved in a dispute about the reasons for the Second World War.

Jonathan Sumption

Better recognised as one of the country's most fearsome barristers, Sumption is also a respected medieval historian. His history of the Hundred Years' War is regarded as a masterpiece.

...vs the 'tele-dons'

Dan Snow

The poster boy of a new generation of on-screen historians, Snow started in 2003 with a documentary on the battle of El Alamein co-presented with his journalist father, Peter Snow.

Lucy Worsley

The historian, who dresses in period costume to make the past real, is chief curator for Historic Royal Palaces. She responded to a jibe from historian David Starkey by saying he resembled a "cross owl".

Simon Schama