I received another lesson in how to travel painlessly this week.

I spent four days in Denver, meeting more lovely people who want to celebrate the 50th anniversary of Doctor Who (about which I will expand in this column soon). As usual the destination and its citizens were delightful and welcoming. The process of getting there, of getting anywhere today is seems, was less convivial.

I have learned to minimise the contentious items in my hand luggage, all liquids removed or in my checked in luggage, along with anything that might be deemed a potential weapon.

I have discovered that putting my laptop in the suitcase that I check in is also a bad idea. Apparently, that is why my bag was opened twice last time I went over there and found my clothing stuffed back in a jumble.

My mistake this week was buying a ham sandwich in Boots airside at Heathrow. I did so because I have a cheese allergy and bitter experience has taught me that more than 50 per cent of airline food has cheese in, on or around it.

There is no ‘no-cheese’ option that leaves me with all the other stuff I can eat. In fact there is no ‘no cheese’ option available. So rather than survive on a dry roll or biscuit at 30,000 feet for nine hours, I decided to take a sarnie with me. In the event, unusually, there was a totally cheeseless meal available. My sandwich therefore was uneaten as I passed through immigration control in Denver. The official asked me if I was bringing food in with me and I replied casually, anticipating that this was okay, that I only had a ham sandwich.

He gave me a basilisk stare and wrote SANDWICH in huge red letters across my landing card and directed me to the customs hall, where I was ordered to join a queue for examination by the officers of the Agricultural Department.

Forty five minutes later I had my ham sandwich confiscated.

When I resignedly suggested that I could have saved myself a lot of time at the end of long flight by eating the darn thing in the baggage hall, I was told that I would have been arrested had I done so, as eating in the baggage hall was a federal offence.

Phew, thank goodness I don’t chew gum or bite my finger nails!

Traveller beware.