Other travellers often store rubbish in seat pockets, including used tissues and dirty nappies stuffed, the US doctors claimed.

London - The danger of catching a tummy bug on holiday could be highest before you even set foot abroad – after doctors warned that passenger jets could present the biggest risk.

Aircraft tray tables, seat pockets and in-flight magazines were the “germiest places”, they said.

Other travellers often store rubbish in seat pockets, including used tissues and dirty nappies stuffed, the US doctors claimed.

In an editorial on its website, US healthcare firm Drexel Medicine also said tray tables were sometimes used for changing nappies – so travellers should clean theirs with a disinfectant wipe.

It also suggested they use hand sanitiser before controlling touchscreens that show films in the headrest in front, adding: “Nearly everyone who sat in your seat before you touched that screen – there is no way of knowing where their hands had been.”

In-flight magazines could be riddled with germs because they are only binned when a new issue comes out.

The firm also said passengers should only use plane toilets when ‘armed’ with disinfectant wipes and hand sanitiser, and use paper towels to lift the loo seat.

It added: “Airplanes are filled with germs. When you cram people in a tight space for a few hours germ accumulation is inevitable.”

But critics said the advice was over-zealous. Travel expert Brian Cohen said passengers should simply wash their hands.