In the early decades of television, some of the considerable snobbery that the medium suffered came from lovers of novels: teachers and parents would exhort regular viewers to lower their eyes to a good book rather than level them at the screen. The later coinage by writers for the box in the corner such as Dennis Potter and Steve Bochco of the term “novel for TV” – to describe the multi-strand multi-episode series – was sniffed at by some practitioners of printed fiction.

These days, though, celebrated novelists seem to be competing as cheerleaders for reading’s once-disreputable rival. Endorsing the BBC’s planned adaptation of the His Dark Materials books this week, Philip Pullman – whose work has previously been adapted for cinema, theatre and radio – suggested that TV is especially suited to the dramatisation of long and complex fiction.

Pullman’s tribute echoes a recent comment by Sir Salman Rushdie at the Cheltenham literary festival that TV box sets are now increasingly competing with novels as an immersive fictional experience. The Nobel laureate Orhan Pamuk also expressed concern, during a recent Guardian Live event, at the number of people who now tell him they prefer to get their stories from the screen rather than the page.

Pullman says that series such as Game of Thrones and The Wire have shown him that TV is able to achieve “depths of characterisation and heights of suspense by taking the time for events to make their proper impact and for consequences to unravel”.

Kit Harington as Jon Snow in Game of Thrones. Photograph: HBO

As a committed Dickensian, the writer of His Dark Materials will be well aware of the often-remarked structural connection between the 19th-century novel and the long-form TV drama: both were written in the form of periodic serials, with plots and longevity to some extent affected by public response.

The greater overlap, though, is less in the division of the material than, as Pullman acknowledged, in the length and depth. The longest movies – even in the days when intermissions expanded the possible span – cannot spend the tens of hours with a character or narrative that are allowed to writers and actors in The Wire, The Sopranos or Transparent.

This love-in between novelists and television, however, raises a couple of worries. When Potter and Bochco spoke of the “novel for TV”, they meant scripts written originally for television but which aspired to the density of novels. The compliment from Rushdie, who recently wrote the pilot for a TV series that did not proceed to production, also referred to such projects, of which a recent example in British TV would be Sally Wainwright’s Happy Valley.

A recent example of a ‘novel for TV’ – the BBC series Happy Valley. Photograph: BBC

What Pullman seems to be suggesting is that the shaping and pacing of a TV serial are better suited than a movie to the adaptation of novels, which is less of a revelation: the books of John le Carré have been generally better served on the smaller screen and it seems unlikely that Hilary Mantel had to agonise much before granting the rights in the first two parts of the Wolf Hall sequence to the BBC rather than to Hollywood. The default decision of a TV drama department with a slot to fill is already to option a novel, and it would be a pity if the flattery of the medium from Pullman leads to producers being even more nervous of completely new work.

I am also slightly worried by the promise from the producers of the TV version of His Dark Materials to “sound every note” in the books, with the implication that the BBC series will be more “faithful” to the source stories than the 2007 film The Golden Compass was.

Adaptation of a literary work to another medium, though, is a rare area of life in which absolute fidelity is a grievous sin. The story of Sir Alec Guinness crossing out speeches or even pages in the scripts for his performance as George Smiley in the BBC’s Tinker Tailor Soldier Spy, arguing that he could convey the same information with a look or silence, showed an understanding that a screen version needs to do very different things to achieve the same effects as a book. The way in which social media have offered book-lovers a chance to monitor changes or omissions in the televised text risks TV adaptations that are true to the original but so inclusive of it that they become gluey viewing.

Whether written from scratch or from a bestseller, television drama should aim to be a challenger and competitor to the published novel rather than a subservient disciple.