People booking foreign holidays risk being caught out by unfamiliar laws by failing to research their destination, the Foreign & Commonwealth Office has warned.
More than a quarter of consular assistance cases were for arrests or detentions last year, it found.
Many could easily have been avoided by researching in advance, according to the FCO.
Holidaymakers have faced fines or worse for playing bingo, eating while sitting on a monument or feeding pigeons.
The FCO last year dealt with 19,244 consular assistance cases, including 5,435 arrests.
It said alcohol, drug and cigarette laws varied by country, warning that it was vital for British citizens to familiarise themselves with the relevant laws.
For example, while Holland had a reputation for being tolerant of “soft” drugs, this was only the case in designated areas and possession could carry a prison sentence.
Consular services director Charles Hay told the BBC: “Every year British nationals find themselves on the wrong side of the law unexpectedly, resulting in fines or in some cases arrests or even jail sentences.
“It is important to remember that laws and customs can vary greatly from country to country and what may be perfectly legal in the UK could be subject to a fine or even a jail sentence in another.”
He said that many Britons treated their passport as a “get out of jail free card”.
But while the FCO will always try to help, Hay warned: “We can’t interfere in another country’s legal processes”.
It listed some of the more unusual laws to watch out for, including:
- In Venice it is against the law to feed pigeons, while in Florence it is an offence to eat or drink in the immediate vicinity of churches and public buildings
- In Barbados is an offence for anyone, including children, to wear camouflage clothing
- Fiji prohibits topless sunbathing
- It is illegal to take mineral water into Nigeria
- Chewing gum is prohibited on Singapore’s Mass Rapid Transit (MRT) system
- Taking more than 200 cigarettes into Thailand is illegal
- It is illegal in Japan to use some nasal sprays which are commonly available elsewhere.