I started to grow a beard a few weeks ago on a whim, and in a month I fly to Spain for a family holiday. It has occurred to me that my passport photograph shows me clean-shaven. Will this give me problems at passport control either in Britain on in Spain? Should I shave it off before I go? Tony Paradice, Carmarthenshire

Sunday Times travel expert, Richard Green, responds: It's absolutely fine to keep your hair on, according to photograph guidelines from the UK passport agency, which say there's no problem in arriving at immigration with a beard that isn't in your passport photo, or being clean-shaven with a bearded picture for that matter.

It's not so much how much hair you have, but where it is that's the issue.

You can dye your hair, grow dreadlocks, shave it all off, whatever takes your mood, but a rogue few strands of long hair across an eye is a different matter.

It's because of the new biometric recognition techniques that are being phased in to deal with increased security. The area around the eyes, nose and mouth, is measurably unique, and scanning equipment uses the precise distances between these facial features, plus the patterns on the iris, to allow for automatic recognition. Hence for the purposes of passport photos, glasses partly obscuring the eye, or hair dangling over the eye, aren't allowed.

What used to be a bit of fun; slipping into a photo booth and practising poses for your passport, is now a more sombre business, with no "obvious grinning or raised eyebrows" permitted, and no teeth exposing smiles. For full details of the do's and don'ts on a passport photo, visit www.passport.gov.uk/general_photos.asp.

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