D B Fluid Control Ltd  (Glasgow)
	D F M/Lynch  (Bangor)
	D G Controls Ltd  (Swadlincote)
	D S P Electronics  (Mold)
	D. Wheatland Engineering  (Redhill)
	D.A. French Engineering  (Radstock)
	D.C. & R. Ault  (Greenford)
	D.M.G. Control Systems Ltd  (Washington)
	D.P. Fabrications Ltd  (Kempston)
	D.S.K. Security Ltd  (Hockley)
	Daco Scientific Ltd  (Aldermaston)
	Dacon Fabrications Ltd  (Gateshead)
	Dairy Pipe Lines  (Essex)
	Dale Engineering Co.  (Chard)
	Dalkia Energy and Technical Services Ltd  (Portsmouth)
	Dalkia Utilities Services P.L.C.  (Northolt)
	Dalling Automation  (Huntingdon)
	Dane Engineering
	Danebridge Engineering Co. Ltd
	Danfoss Ltd  (Denham)
	Daniel  (Stirling, Scotland)
	Daniels Fans Ltd   (Llanelli)
	Danielson Ltd  (Aylesbury)
	Danmark Impeller Engineers Ltd   (West Bromwich)
	Dantec Electronics Ltd  (Bristol)
	Danum Pneumatics  (Doncaster)
	Dassault Systemes   (Paris, France)
	Data Display (UK) Ltd  (Waterlooville)
	Data Entry Products Ltd  (Newburn)
	Data Harvest Group Ltd   (Leighton Buzzard)
	Data Systems & Solutions Ltd  (Gateshead)
	Data Track Process Instruments Ltd   (Christchurch)
	Datalogic Scanning, Inc  (Eugene, USA)
	Datamars
	Datamonitor Europe  (London)
	Datapaq Ltd   (Cambridge)
	Dataracks  (Cottenham)
	Datastor Systems Ltd   (Congleton)
	Datastream Systems (UK) Ltd   (Theale)
	DataTaker Ltd  (Letchworth)
	Datel (UK) Ltd   (Tadley)
	Datoc Engineering Ltd  (Salfords)
	Datum Electronics
	Datum Precision Engineering Ltd  (Radstock)
	Dauns Auto Technology Ltd  (Inverness)
	Dave Burlow Engineering  (Cheltenham)
	David Brown Gear Systems Ltd (A Textron company)  (Huddersfield)
	Dayton   (Lichfield)
	DED Ltd  (Romney Marsh)
	Dedicated Engines   (Letchworth)