The BRE has warned that misuse of its green products selection guide could lead to a generation of badly performing buildings.

Concerns had been raised after Milton Keynes council made it mandatory for all new buildings to use materials with high ratings from the online tool, called the Green Guide.

The guide rates different products on an A+ to E scale, according to the environmental impact of the materials during manufacture. Designers win BREEAM and Code for Sustainable Homes credits when specifying materials with a high rating.

However, Paul Gibbon, BRE’s global director of materials, said insisting on materials that are given a high manufacture rating could lead many materials to be excluded, despite being better performing when in use.

He said: “Let’s nip this in the bud before we get 50 councils saying people have to specify A+ materials.”

John Tebbit, industry affairs director of the Construction Products Association, which jointly issued a statement with the BRE, said it could lead to a generation of gas-guzzling buildings. He said: “A good building is more than the sum of its parts. The nightmare scenario is a building constructed from A+ rated materials that uses vast amounts of energy.”