Never, ever look at your face in a car 'vanity' mirror. 'Vanity-destroying' is more like it. Quite the cruellest mirror you're ever likely to encounter.

However... if you've had a close encounter of the disturbing kind, up close and personal with some lines that you didn't know you had (it happened to us, recently), you need to know about this.

A new 'line-blurring' primer from Guerlain, it's quite the wonder-worker, in our opinion.

From the teeny tube atop the nozzle, it appears as a white cream – but rapidly sinks into skin, helping to minimise the appearance of lines and pores. It's not completely matte, but creates a velvety base over which to apply your chosen foundation – which, even in the recent hot weather, it was helping to keep in place for much longer. (Our other favourite Guerlain primer, Baby Glow, is more radiant and glow-y, if you like that finish.)

Make-up glides onto skin beautifully – and there's one heck of a pleasure factor when you apply this, since it has the signature, so-pretty Guerlain 'parma violets' scent familiar to lovers of the Météorites range.

We're definitely finding room in the make-up bag for this. (And possibly petitioning to ban all in-car mirrors except those required for safety.)

Guerlain Blurring Active Base/£32 for 30 ml at johnlewis.com