The majority of people are unable to recall the mobile numbers of their nearest and dearest. Indeed, the results of a recent report have sparked fears over the impact of technology on memory.
70 per cent of respondents said that they did not know the mobile number of their closest friend, while just over 50 per cent said that they could not think of their parents' contact details without technological aid.
There are fears that people will be unable to get in contact with anyone should they be unable to access their mobiles due to loss, theft or a dead battery. In an emergency this could have serious consequences, according to security firm CPP.
90 per cent of respondents who participated in the online study could not retain a mobile number five seconds after being shown it.
CPP's Michael Lynch: "Our research shows that people are so heavily reliant on their mobile phones, that they would be lost without them [...] Over four in ten victims have admitted that they have lost contact with friends when they have lost or had their phones stolen."
Most people must deal with multiple passwords, PINs, number plates and various bank account details in order to function on a daily basis. For many this consumes all capacity to retain numbers, resulting in what experts refer to as 'numerical amnesia.'
64 per cent of respondents said that they were concerned about misplacing their mobiles because the data stored on them is extremely important. However, only half of this group actually take the time to backup their mobile phones to their PCs.
Mr Lynch added: "Britons' inability to recall numbers of their nearest and dearest means many could be in a very tricky and distressing situation if their phone is lost or stolen.
"This shows us that mobiles have literally become people's lifelines."
With recent advances in mobile technology, contact details are not the only significant pieces of data stored on a standard phone.
A third of the 2000 respondents said that they would be concerned about losing their phones because of the photographs contained on-board, whilst 25 per cent would want to hold onto SMS texts.
44 per cent of respondents did not have their national insurance numbers memorised, whilst 53 per cent had difficulty recalling their bank account details.