This paper describes the results of a study commissioned by the Foreign and Commonwealth Office from Research Surveys of Great Britain (RSGB) to determine whether the World Service is effective in communicating a positive impression of Great Britain to the audience. The study was based on the results of an interview survey of 750 adult residents of Lisbon in Portugal which was carried out in April and May 1990. In essence, the survey was designed to facilitate comparisons between listeners to the World Service (both via direct transmissions and rebroadcasts) and non-listeners in terms of their attitudes towards Britain. However, since attitudinal differences between these groups could simply be due to characteristics, other than exposure to the World Service, on which listeners and non-listeners are also differentiated, it was necessary to employ particular statistical techniques in order to make comparisons which were unbiased by the effects of these other factors. By means of this statistical analysis, groups of people were examined who were similar in respect of other characteristics likely to be predictive of relevant opinions about Britain. Scores derived from a number of relevant summary measures (reflecting different aspects of a battery of attitudes towards Britain) definitely tended to be higher amongst listeners than for non-listeners.