Primeval, ITV1, 4.30pm
Foyle's War, ITV1, 9pm

I hope never to come face-to-face with a flesh-eating, sabre-toothed gorgonopsid from the long-ago Permian era. It's an aggressive, heavily-armoured 12ft-tall blighter that runs around on its muscly hind legs, yon gorgonopsid, by the way.

Should I meet one, however, I now know how to kill it. According to Primeval, all you have to do is drive a chunky four-wheel-drive Toyota into it to stun it. Then you empty a sub-machine gun into its chest.

Result: one dead gorgonopsid.

On the face of it, this doesn't seem the most eco-friendly thing to do - but then again, gorgonopsids did lack the nous to avoid becoming extinct more than a million years ago, so there was no great loss in offing one, I suppose. The only reason it began terrorising Primeval's 21st-century cast was down to one of those darn rips that opens up in the very fabric of time every so often.

If I stick with Primeval, the show may eventually prove useful in telling me how to stitch up such time-fabric ruptures, I suppose. If I'm honest, though, I'm not sure I will stick with Primeval (hope I don't suddenly tumble back through time's ripped fabric to somewhere appalling, such as the seventeenth century: it would be like experiencing life as an Old Firm fan . . . shudder!).

But I digress. Primeval is a less-demanding version of Doctor Who: its time-travelling threats can simply be shot and run over, rather than laboriously understood and then cleverly undone.

Primeval is also a bit like ET, in that it featured a little kid chumming up with a cute green flying lizard that chirped and blinked at folk in a most endearing fashion. Like the gorgonopsid, this crittur had wandered into 2007 through a hole in the sundered time-fabric.

And Primeval is also a bit like the Indiana Jones movies in that, for its hero, it's got a self-contained scientist in a memorable jacket. Archaeologist Indiana Jones's jacket was a covetable battered brown leather job; palaeontologist Professor Nick Cutter's is a fetching lovat-green safari-style effort with utilitarian patch-pockets.

As Professor Nick Cutter, wur ain Douglas Henshall adopts a curious vocal delivery as he stares into whatever bit of the middle-distance is handiest. Mostly, Douglas slips into staccato, throttled-back Sean Connery mode, lessening the latter's sibilance (or "lesshening the latter'sh shibilance," if you inshishst).

He throws in Ken Stott's randomly emphasised monotone, all the better to give an important sound to guff such as "Darwin provides most of the answers . . . it's the pieces that don't fit that interest me" and "I'm going to go through the anomaly - if you want to stop me, you're going to have to shoot me". Bang, bang.

What to say about another time-travelling caper, Foyle's War, set in Hastings during the war-blighted, severely-rationed days of December, 1942, now returning for its fifth series?

In giving Detective Chief Superintendent Foyle his trademark air of enigmatic disinterest, Michael Kitchen impersonates a chemistry professor waiting in a High Street bus queue beside the common herd. Whenever some frightful oik vouchsafes an unsought opinion on the late-running of the No 42, Foyle studiously avoids his gaze while plucking a vague-seeming-but-actually-incisive query out of the ether. This week, the vague-seeming-but-actually-incisive query went along the lines of "And when did you stop beating someone else's wife to death?"

Hence, this week Foyle solved two murders, an instance of police perjury and one accidental death, as well as foiling a bank robbery. All this, and Honeysuckle Weeks playing posh popsy Samantha Stewart as a twitchy, oddly bewitching combination of Joyce Grenfell, Christine Hamilton and Princess Anne. Not so much Foyle's War as royal phwoar.