Harris Tweed - as worn by Dr Who.

Well, they say a Harris Tweed jacket will last a lifetime but no one said the garment would withstand a Timelord's regeneration.

The first pictures of the new Dr Who, Matt Smith, and his companion Amy Pond, played by Inveress star Karen Gillian, were released today.

The Doctor was sporting a natty bow tie and a tweed jacket but the burning question on my mind was - what kind of tweed jacket?

Was it the enduringly strong Harris Tweed jacket hand-woven in the Hebrides and beloved of crofters and aristocrats for generations and now the talk of fashion houses across the universe.

Was it the mythical Harris Tweed jacket worn by the heroic George Mallory on his unsuccessful 1924 attempt to climb Everest? Was it, in short, the genuine article?

"Vintage Harris Tweed" is what the BBC Press Office told me which is a kind of a mixed marketing blessing.

To have Harris Tweed endorsed by a time-traveller is quite a fillip - as timeless as Dr Who and other gauche advertising lines spring immediately to mind.

It proves the material is so durable that it lasts several lifetimes but it does raise the obvious style quandary that teenagers across the land will now face - to buy a new one or just raid your grand-uncle's wardrobe.