If you’re still a physical media kind of person – and rumours of the death of the format are greatly exaggerated, so you really should be – and you only plan on buying one archive TV DVD boxset in 2016, you need to make sure it’s Network’s long-overdue and comprehensive re-release of the classic ITV children’s series Timeslip. First screened in 1970, this intelligent, well-crafted twenty-six-episode series, although enjoying none of the profile of its louder, ballsier sci-fi stablemates from the 1960s and 1970s, is often cited as one of the most memorable and downright important genre series ever screened on British TV. It’s a series which has certainly stayed in the imaginations of the audience who were captivated by it at the time despite its lack of extravagant special effects and quite possibly because of its emphasis on concept and character. Timeslip was decades ahead of its time with storylines involving cryogenics, cloning and global warming and it explored the idea of time travel with far more integrity and intelligence than any of its contemporaries, even the much quainter Doctor Who.

In The Wrong End of Time, the first of four serials, Liz Skinner (Cheryl Burfield) and her parents, along with young Simon Randall (Spencer Banks), the son of Liz’s father’s best friend, are enjoying a lazy summer holiday in the remote village of St Oswald. Simon, whose mother has recently passed away, is the studious sort but eventually Liz manages to prize him away from his reading and they wander off to investigate their surroundings and the crumbling ruins of a wartime naval research station. Here, in amongst the rotting fence posts, they find something quite extraordinary; an invisible, shimmering forcefield – a barrier. Liz finds a gap in this barrier – and promptly disappears. Alarmed, Simon follows her into the invisible ‘gap’ – and the pair suddenly find that day has become night and that the deserted naval base is no longer rundown and abandoned. They discover, to their astonishment, that they’ve somehow travelled back in time to the 1940s and that the research station is working on the development of laser technology for use in the ongoing war effort. The station’s commanding office Traynor (Dennis Quilley), an older version of whom they have already encountered in St Oswald, is brisk and officious and Liz realises that fresh-faced young rating Frank Skinner (no, not that one) is actually a younger version of her own middle-aged Dad who, back in Liz’s time, can’t quite remember what happened at the naval station and why he was invalided out of Service before the end of the conflict.  Then a shock group of Germans arrive and requisition the base…

If you’ve never seen Timeslip, if you weren’t part of that generation which thrilled to the twists and turns and the bustling imagination of this glorious series back in 1970, you really owe it to yourself to grab a copy of this new DVD set as soon as possible. Whilst the show is aimed at children and the two lead characters are squeaky-voiced teens (it’s entirely possible that Liz’s nails-across-blackboard screeching will quickly become an issue as you make your way through the series), the writing is intelligent, measured and wonderfully prescient. During its development its initial six-episode commission was quickly extended and certainly this reviewer can still recall his falling-off-the-seat astonishment at the end of episode six when Liz and Simon finally escape from the 1940s, crawl through ‘the time barrier’ (as it becomes known) and find themselves in an entirely-unexpected frozen Antarctic (albeit utterly studio-realised) wilderness. The second serial, The Time of the Ice Box, is set in a sterile research establishment in 1990 where Liz encounters future versions of herself and her mother and Simon becomes fascinated by longevity experiments being carried out under the watchful eye of the brusque and oddly-inhuman Professor Devereux (John Barron). The eight-episode Year of the Burn-Up is a bit more of a slog and sees the travellers pitch up in an alternate 1990 where global warming has turned England into a tropical jungle. The final six episodes, Day of the Clone, drift between 1965 and 1970 and offer a final confrontation between Liz and Simon and various versions of characters who have been influencing their lives since their first encounter with the time barrier months earlier.

Although much of Timeslip was created and written ‘on the fly’ as the series was repeatedly extended, the through-line of the narrative stands up remarkably well and continuity is tight as the series becomes increasingly convoluted and moves away from its initial intriguing and innovative premise of ‘time-sensitive’ children being able to access the “energy” of traumatic historical events or incidents and thus able to access the past itself. Mature scripting, eschewing the silly monsters and far-fetched high camp storylines of many similar shows of the era, allows the series to develop as a proper, full-blooded, thought-provoking drama which never talks down to its target audience of youngsters and, as a consequence, Timeslip found itself appealing equally to a more sophisticated adult audience fascinated by the show’s web of paradoxes and forward-thinking concepts.   Obviously the show now looks its age – teenagers like Liz and Simon just don’t exist anymore – but the series still works because of the earnestness of its performances (newcomers Banks and Burfield match their more experienced fellow cast-members such as Quilley and Barron beat for beat) and its determination to tell a gripping, intelligent, wildly-imaginative story which never tips into the realms of the fanciful and the far-fetched.

Network have drawn together a comprehensive collection of supporting material, much of which has only been available to the show’s small but passionate fan community; the 93-minute Beyond the Barrier making of documentary hails from 2009 and is especially notable for the startling number of  cast and crew who have since passed away; raw footage of a cast visit to the show’s time-barrier location (the famous fence posts are still standing despite a massive residential development in the area); convention footage; and a charming 2005 fan-produced mini-episode (script edited by series producer Ruth Boswell) which sees Liz and Simon returning to the barrier thirty years later. New material includes an extensive photo gallery and Andrew Pixley’s exhaustive souvenir booklet which is really the last word on the making of this classic, iconic piece of 20th century children’s television. Timeslip – much of it was filmed in colour but due to the junking of the original tapes, only one episode remains in colour – is over four decades old but it’s still a terrific and essential piece of genre television which will not only find favour with its ageing original audience but should also appeal to newcomers tired of the empty spectacle of much of today’s TV sci-fi.  Find time for Timeslip – it’s a trip through the TV time-barrier which you simply won’t regret.

Special Features: Production booklet / Documentary / Photo gallery / Conventions footage / Mini-episode / Location visit footage

TIMESLIP: THE COMPLETE SERIES / CERT: U / DIRECTOR: JOHN COOPER, PETER JEFFERIES, RON FRANCIS, DAVID FOSTER / SCREENPLAY: BRUCE STEWART, VICTOR PEMBERTON / STARRING: SPENCER BANKS, CHERYL BURFIELD, DENNIS QUILLEY, IRIS RUSSELL, DEREK BENFIELD, JOHN BARRON / RELEASE DATE: OUT NOW