Fairweather, who lives in Balcombe in West Sussex, was given the award in recognition of a career that including editing the AJ from 1973 to 1984. With Jan Sliwa he co-wrote the AJ Metric Handbook, first published in 1968. It sold more than 100,000 copies.
For more than 50 years Fairweather wrote, lectured and broadcast about prison architecture, culminating in chairing the RIBA committee that reported to Lord Woolf's enquiry following the riots at Strangeways Prison in 1990.
Speaking to the AJ, Fairweather said: 'I was completely surprised. I was awarded an OBE [in 2005] and I thought that was it. I will be 80 next year – it's rather sweet really.'