asked the Parliamentary Secretary to the Ministry of Civil Aviation whether he has yet collected the evidence to indicate what broadcast sources are interfering with British aircraft communication services in South-East England and the Midlands.

The evidence shows that the main broadcast source concerned has been the Daventry (Overseas) Service, but other B.B.C. short-wave broadcast stations have also been responsible to a limited extent. The interference is due to an harmonic of the transmitted frequency and as soon as this was established the B.B.C. took immediate measures to effect a remedy. Reports from pilots show that some improvement has been effected. Technical staff from my Ministry are at present collaborating with the B.B.C. engineers with the object of eliminating the interference altogether.

Has the harmonic in question been transferred to the Cabinet?