1965-67 Partner in Silver, Penney, Architects, Cambridge. 
1967-70 Principal in Nathan Silver, Architect, London.
1970-72 Associate in Louis de Soissons Partnership, London.
1972-73 Principal in Nathan Silver, Architect, London. Typical commission: Leith's Restaurant, Kensington Park Road, London.
1973-78 Partner in Feilden & Mawson, Architects. Partner in charge of London office. Typical commissions: two luxury hotels in Norfolk; Jubilee Tourist Centre, Shaftesbury Avenue, London. Typical responsibilities: managing architect for conservation work at St Martin-in-the-Fields; managing architect for all work at Queen Mary College, University of London; managing architect for residential property of the Church Commissioners for England on the Hyde Park Estate.
1978- Principal in Nathan Silver Architects, London. Typical commissions: consultant to London Borough of Tower Hamlets and Tower Hill Tourist Trust as architect for Tower Hill Tourist Centre; consultant to British Film Institute for conversion and extensions to National Film Theatre-- provision of a third cinema with television and other technical screening capabilities, an extended bar and restaurant and outdoor screens; luxury hotel conversion in Islington; conversion of ground floor and mezzanine of the Theatre Museum, London, as performing arts bookshop/café; interior alteration and redesign of luxury accommodation, Westminster; major extension to existing industrial buildings with a graphic arts studio/workplace development; multiplex cinema/arts centre for London SW1; project for design of Danish Royal Library, Copenhagen (with Schwartz/Silver Architects); consultant to Schwartz/Silver Architects for New England Aquarium, Davoli house and Princeton University Humanities Building, USA; residence for Anna Raphael, Belgravia; design of new public house, The English Channel, for Horseferry Road, London; conservation-led refurbishment of a 400-year old pub, The Seven Stars, in Carey Street, London; design and construction of new pub, The Bountiful Cow, in Eagle Street, London.