Description of the mobile phone-based monitoring system (see figure) The system software (T+ asthma, Oxford, UK) can be loaded onto any web-enabled mobile phone. It permits recording of symptoms, medication usage and lung function. Measurements are made with a Piko meter (a prescribable electronic meter which records both (FEV1) and peak expiratory flow (PEF)). We have opted to record FEV1 because it is a component of the ACQ,24 and the correlation between Piko and spirometry FEV1 is excellent (r=0.98).25,26 Data transmitted to a remote server are analysed and the latest reading returned to the mobile phone, compared with the preceding week's recordings and a prompt for using 'preventer' medication. In addition, the patient and their clinician can access the record via a password-protected website.C. Design of the research A six month single-blinded randomised controlled trial