Only one in seven Brits stop and turn off their cell phones before having sex, according to a report touted as the largest ever to examine how mobile phones have changed British life.

More than 16,500 people participated in a survey by The Carphone Warehouse, an independent European cell phone equipment and services retailer, and The London School of Economics and a Labour Party leader. Mobile Life, a forum established by The Carphone Warehouse, released the results Monday. Researchers looked at several aspects of life, but they pointed to sex findings as the most surprising.

The study found that while only 14 percent of those surveyed said that they switch their cell phones off, another 11 percent switch them to silent, meaning one in four people disable their device " one way or another " before having sex. When asked to describe the circumstances under which they would turn their phones off or silence them, more people listed movies, restaurants, meetings or nighttime than sex.

The survey also found that more than half (54 percent) of the people between the ages of 18 and 24 sent or received sexually explicit text messages, and a quarter sent or received a sexually explicit picture or video.

More than half (57 percent) of all mobile phone users in that age group sent or received invitations to a date by text, and more than one-fifth reported receiving a "Dear John" text message, according to the Mobile Life report.

Many people said they believe it is reasonable to use a text message to avoid a conversation, with 33 percent reporting it is reasonable and another 42 percent reporting that it can be reasonable if done considerately.

One in four mobile phone users said they did not think that sending a flirty text message was a form of cheating.

Twenty-one percent of respondents said they use their cell phones to deter people from approaching them. Among women under 25, the tactic was more popular, with 55 percent saying they used their mobile phones to deter unwanted advances from men.

The study also found that young adults place more importance on their mobile phones than television, and sending text messages has surpassed talking as the most popular cell phone activity.