Repeated frantic searches of pockets are the best way to track down mislaid keys, passports, air tickets and credit cards, according to behavioural scientists.

After months spent studying holidaymakers at airport check-in desks, researchers from the University of Strathclyde have concluded that swearing, smacking children and shouting at other passengers also helps locate missing items.

One traveller admitted: ‘It seemed hopeless until I lost my temper, tore off my jacket and ripped my inside pocket open and there was my passport. I’d looked in that pocket about eight times before and it was in there all the time! What am I like?’

Specially trained airport staff are being brought in to offer behaviour-supporting counselling to frenziedly self-searching passengers with key phrases like ‘It must be in there somewhere’, ‘Have you tried that pocket?’ and ‘When did you last have it?’

The research also found that accusing other family members of deliberately moving items or leaving them behind can also speed the discovery of missing essentials, usually in the first place that was searched. Professor Dougal Saltire is advising all travellers who have mislaid anything to furiously rummage through baggage and pat their pockets repeatedly. He said: ‘We’ve no idea why but it seems to work in the end.’

He went on: ‘What seems at first glance to be a hysterical, chaotic outburst is in fact a genetically imprinted possession location process that can be traced back to at least the Romans and the many lost valuables that they recovered and did not mislay in pottery urns to be found many hundreds of years later.’

The research group is also recommending that departing travellers follow their other instinct to go round their homes and check taps are off at least six times, with electrical plugs requiring a minimum of eight inspections by at least two members of the family.