Professor David Wallace, Vice President of the Royal Society, has written to Ivor Caplin, the Minister responsible for defence estates, to seek greater progress in finding solutions to the potential problems posed by wind turbines to air defence radar.

The letter states: "My understanding is that the current MoD policy appears to reject any wind development application within 74 km of air defence radars. With 13 such installations, this effective moratorium covers a fairly significant area of the UK. Understandably, the MoD has concerns over the effects that wind farms may have on radar in terms of personnel safety, especially for low flying aircraft and the potential consequences of compromised radars with regard to national security. It nevertheless concerns me that the restrictions imposed by the MoD are at odds with the rest of Europe, where only Germany imposes a ban, which is set at 5 km."

The letter enquires: "How much still needs to be done and are there issues that still need to be addressed before the current restrictions,imposed by the MoD, on wind farm developments, can be reviewed?" It further asks: "Given the technical solutions being developed, how long do you consider it will be before your policies can be brought more into line with our European counterparts?"

The Royal Society has also raised its concerns with the Department forTrade and Industry, which is responsible for promoting the development of renewable energy technologies.