About one in three (31 percent) of those questioned in the survey, commissioned by the Science Museum in London, for its Science of Spying exhibition, said they covertly listened in on their partner's conversations.

A small number of the 1 129 people questioned, said they had even secretly recorded their partner's telephone conversations, using Dictaphones or other such taping devices.

This method was the most popular with the over-55s age group, where one in 20 (five percent) put their hands up. This age group also included people using webcams and GSM tracking devices.

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