Your correspondent Ron Hughes (NCE 30 November) asserts that a consulting engineer 'undertakes to deliver a facility that is fit for its purpose'. He is wrong.
Consulting engineers undertake to exercise reasonable skill and care in carrying out their agreed duties.
They do not 'deliver a facility' - that is the contractors' function - and in undertaking their designs they cannot be expected to foresee what is beyond the accepted canon of current knowledge, the current 'state of the art'.
It is right that this should be so. To place any higher burden on designers would stifle innovation and progress.
Clare Bristow, Association of Consulting Engineers, Alliance House 12 Caxton Street, London SW1H 0QL