In the first of five semi-connected half-hour dramas devised through improvisation and directed by Dominic Savage (Freefall), David Tennant stars as Nick, a happily-married father of two whose comfortable, contented life is plunged into emotional disarray by the reappearance of the true love of his life.

Serena (This Is England’s Vicky McClure) jilted Nick back in the day because she didn’t see a future in their relationship, disappearing completely and apparently permanently from his life. Now, seventeen years on, she’s back and full of regrets about their split. Can Nick resolve the past, recreate the glory days in the present and restart anew with Serena, or must he reflect, resist and return home to wife Ruth (Downton Abbey’s Joanne Froggatt)?

The themes of all five episodes of True Love are powerful, affecting and immediately recognisable, but the notion of old hopes and heartbreaks re-emerging from one’s emotional history is particularly resonant.

Does love last forever? Can romance be rebuilt, years after crumbling to dust? What would you do if the ex of all exs resurfaced, dragging long-neglected feelings out of the soul’s darkest corners? The safe and sane answer is to misunderstand the advice of Stephens Stills and love the one you’re with, but Nick – like so many of us – finds it impossible to merely dismiss the reappearance of his life’s one true grand passion.

‘I’ve missed you… a lot,’ Serena says as they walk along the waterfront at Margate, an undercurrent of unforgotten intimacy running beneath their awkward, stilted conversation. Tennant and McClure are superb together, the lack of a script giving their dialogue an economic tautness, their pauses, hesitations and laughter as natural as they are familiar.

Admittedly, some of the other scenes – particularly the moment when Serena runs into Ruth in the street – don’t have that same direct click of realism, but the two principals, Tennant in particular, are instantaneously and perfectly believable throughout. Anyone who had a heart – as Cilla Black might say – will be able to place themselves into the position of either character.

Even if you can’t empathise to that degree, it would take someone with the sensitivity of a breezeblock not to feel for Nick as he agonises over what to do, or Serena as she struggles to put right what went wrong in the past, or even Ruth, who clearly knows something’s going on between her husband and his old flame but can’t – daren’t – bring it up in conversation.

There’s an abiding melancholy running through the episode, the out-of-season seaside scenes of empty promenades and ominous skies echoing with the desolate cries of gulls. It’s clear that no matter which course Nick chooses, more angst will inevitably follow.

While it isn’t established until the very end whether the ties that bind his life together are strong enough to withstand this unexpected emotional upheaval, the questions he is asked and asks of himself are ones which everyone must address at one time or another – and it’s this universality, as much as the engrossing emotional honesty of Tennant, McClure and Froggatt, that make this opening instalment of True Love well worth watching.

Airs at 10.25pm on Sunday 17th June 2012 on BBC One.

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