SAVE the Children has launched a “Phoneless Friday” campaign after finding 2.4 million people “would not be able to cope” if they left their phone at home for a day.

Around 43 million of us regularly use smartphones to contact each other and in just a few years this has transformed the rules of traditional British etiquette, according to researchers.

Nearly all (97 per cent) smartphone users believe breaking up with a partner via text is unacceptable but at least four million people have had it happen to them, the research found.

In response, Save the Children has challenged people to leave their mobiles at home on Friday to “rediscover the forgotten phenomena of face-to-face conversation”.

The charity’s survey of 2,032 adults revealed more people (64 per cent) consider texting while talking to someone ruder than not giving up a seat for someone who needs it (63 per cent), and ruder than being late (54 per cent).

More than half said they find bad phone-related manners frustrating, in particular people who speak loudly on their phones while using public transport (66 per cent), and people who text at the dinner table (53 per cent).

A similar number (48 per cent) said they find it rude when people fail to look where they are going because they are texting, while just over a third consider it poor form to text someone bad news rather than tell them in person.

The research came after an Ofcom report revealed people are spending more than 24 hours a week online, while recent ONS figures showed we send more than 262 million texts a day between us.

Save the Children found that, on average, smartphone users would be willing to pay £47 to retrieve their phone if they lost it.

Comedian Dom Joly, an ambassador for Save the Children, drew attention to poor phone etiquette with his Big Phone Guy sketch on the show Trigger Happy in 2000.

The character talked loudly on an enormous fake mobile phone in quiet or public places, or at inappropriate moments.

Joly said: “There was something cringeworthy but recognisable about him. We’ve probably all had a phone conversation a little too loudly or walked into something because we’re texting.

“Phoneless Friday is giving people the chance to get back to the simpler time of pigeon carriers and paper map reading whilst feeling great about ignoring your friends, because it’s all for an incredibly worthy cause.”

Nearly a fifth of survey respondents admitted to committing a phone faux pas of their own, including walking into something while using their handsets, sending an embarrassing text to the wrong person, and getting drunk and sending a message that they later regretted.

A similar number revealed occasions when they stopped listening to someone speaking to them and where they had bumped into something or someone because they were using their phones.

One in 10 also admitted missing their stop on public transport because they were using a smartphone.

Nick Jones, Save the Children fundraising director, said: “Phoneless Friday is a fun new fundraiser to challenge people to get their friends together, give up their phones for one day, and donate.

“Whether at work, at home or in the pub, we’ve all got that one mate who is glued to their phone, so it’s about watching them squirm as they long to check Instagram, or watching them try and work out how to get somewhere without their map app.”

People who want to take part in the event are asked to visit phonelessfriday.org.uk to contribute £5 to the charity, which works towards supporting vulnerable children across the country.