Rank Company Location Year end Annual sales rise over 3 years Latest sales £000s Staff Comment
1 IXEuropeData centre provider East London 2001 644.33% 5,917 110 Raised £66m in venture capital and cancelled flotation at eleventh hour
2 Fasthosts InternetInternet services provider Gloucester 2001 337.88% 4,609 24 A-level project led to firm hosting Rolls-Royce website
3 Caplin GroupFinancial software developer Central London 2001 306.20% 4,838 28 Former pop star now competes with Reuters and Bloomberg
4 AminoElectronic systems designer Cambridge 2001 298.39% 2,071 52 Holds 12 patents for its data transfer technology
5 Wireless Information NetworkWireless services provider Buckinghamshire 2001 270.01% 3,819 54 Service allows the AA to send text messages to members' mobile phones
6 NeoscorpData communications provider Berkshire 2001 260.84% 17,656 109 Its network was used to transmit images from the latest Bond movie
7 VoxarMedical software developer Edinburgh 2001 257.87% 1,673 58 Technology credited with saving marathon runner's life
8 CeloxicaMicrochip software developer Oxfordshire 2001 236.55% 1,908 120 Oxford University spin-out raises £40m in venture capital
9 Essential Network ServicesIT network consultancy SE London 2001 214.16% 2,043 20 Designed plan for digital television network covering 6m homes
10 whereonearth.comLocation services provider Central London 2001 209.84% 2,544 54 Trivial Pursuit producer creates A to Z for mobile phones
11 Zygon SystemsCatalogue software developer SW London 2001 206.51% 1,167 43 Software used by Argos for in-store electronic kiosks
12 Telecom OneTelecoms network provider Central London 2001 201.54% 54,771 35 Telecoms company also runs a digital TV dating channel
13 Cramer SystemsTelecoms software developer Bath 2001 193.37% 12,583 255 Engineer simplifies telecoms technology for BT and C&W
14 TrayportTrading software developer SE London 2001 182.09% 1,085 12 Company claims that 2,700 trading screens worldwide use its software
15 AttendaIT services provider West London 2001 173.33% 7,119 140 Runs Guinness World Records website with 600,000 subscribers
16 RadioscapeWireless software developer Central London 2001 166.56% 4,070 76 Computer animators raise £18m venture capital for software
17 RAW CommunicationsVideo streaming provider Central London 2001 163.77% 5,543 91 Supplies online video presentations to fund managers worldwide
18 MessageLabs GroupManaged technology provider Gloucestershire 2001 150.04% 16,735 262 Identified and named the infamous Love Bug virus
19 SentecTechnology business developer Cambridge 2001 146.66% 2,307 27 Founder began by selling TV sets from a wheelbarrow at the age of 14
20 Lost WaxInternet software developer Richmond 2001 136.03% 4,808 85 Built website for General Motors to auction repossessed cars
21 Sourcing PartnershipsIT services outsourcer Edinburgh 2001 135.42% 17,361 19 Keeps cost down by using network of 300 contractors
22 Pinnacle TelecomTelecoms services provider West Lothian 2001 133.86% 1,097 14 Founder left BUPA to set up telecoms consultancy
23 Rosetta StoneBusiness software consultancy Middlesex 2001 128.76% 1,321 7 Founders name company after ancient Egyptian relic
24 Mistral Internet GroupInternet service provider Brighton 2001 122.69% 4,154 24 Hosts websites for Sony Music and Bacardi Breezer
25 InclarityTelecoms services provider North London 2001 122.56% 3,474 33 Enables users to check e-mails or faxes from any phone
26 Nimbus PartnersBusiness software developer Hampshire 2001 121.76% 1,007 25 Software used to restructure DaimlerChrysler after merger
27 Opal TelecomTelecoms services provider Manchester 2001 120.81% 92,343 191 Founder won MBE for services to engineering
28 ActixTelecoms software developer West London 2001 118.55% 5,188 56 Opened office in Shanghai to target Asian mobile market
29 Question Mark ComputingEducation software developer North London 2001 117.47% 2,653 40 Claims every UK university uses its software to manage exams
30 Process Systems EnterpriseProcess software developer Central London 2001 117.43% 2,084 27 Academics now sell modelling software to BP and Shell
31 NallatechComputing systems designer Glasgow 2001 116.60% 1,300 20 High-performance electronics used to test air-to-air missiles
32 EndXCasino software developer Oldham 2001 114.01% 1,324 16 Supplies 60% of UK casinos and has opened an office in Las Vegas
33 Silver Software ConsultantsTransport software developer Wiltshire 2001 113.48% 1,031 35 Founder set up company in India to recruit programmers
34 KW InternationalTrading software developer SW London 2001 110.74% 8,751 79 Secured £9m of venture capital in 2001 to fund expansion into US
35 AspectiveE-business systems integrator West London 2001 107.53% 16,997 183 Former head of IBM UK builds company through acquisitions
36 UPDATAShare trading software developer Central London 2001 107.10% 2,249 30 Claims to be 10 times cheaper than Reuters or Bloomberg
37 Independent Building SolutionsBuilding systems developer Croydon 2001 106.73% 10,033 63 Sells systems to control building services from lifts to ventilation
38 ShopcreatorE-business software developer Leeds 2001 106.21% 1,018 38 Rejuvenated growth with government small-firms loan
39 ImergeAudio-video systems developer Cambridge 2001 105.61% 1,450 45 Internet-linked audio system allows playback in 16 rooms
40 Aircom InternationalTelecoms service provider Surrey 2001 105.53% 17,660 152 Mobile-phone giant Nokia took 40% stake in January 1999
41 Global BeachE-business software developer SW London 2001 104.89% 6,155 75 Service allowed Nick Faldo to update fans from the Open golf course
42 Zeus TechnologySoftware developer Cambridge 2001 103.11% 1,580 84 Software helps eBay's website handle 20m queries a day
43 iokoDigital media systems integrator York 2001 102.86% 10,083 143 Created Barbox, UK's largest online portal for pubs, restaurants and hotels
44 Eiger SystemsPayment software developer Rugby 2001 102.12% 2,353 22 Claims 470 companies use its software to make payments online
45 RealiseE-business software developer Edinburgh 2001 101.49% 2,901 114 Designed websites for Bank of Scotland and Standard Life
46 Alphatec SoftwarePayment software developer Milton Keynes 2001 100.90% 3,181 42 Software clears cheques for Royal Bank of Scotland and NatWest
47 BOOT ComputersTrading software developer Cheshire 2001 99.37% 2,489 24 Software used by Charles Schwab's UK share dealer
48 ASTRACBusiness software developer Warwick 2001 97.69% 5,856 19 Provides software in 18 countries for clients from Ford to Vatican University
49 SpiritSoftMessaging software developer Central London 2001 96.04% †2,827 42 Software lets incompatible computer systems talk to each other
50 DNA ConsultingDigital media consultancy Central London 2001 95.88% †2,281 37 Developed Sony's interactive TV demonstration for PlayStation 2
51 Fifth Dimension SystemsE-business systems integrator Cardiff 2001 95.65% 2,456 16 Started in an attic in Barry, firm now has purpose-built office in Cardiff
52 edNETInternet services provider Edinburgh 2001 95.34% 1,246 16 Father helped medical-student son start business at university
53 CDC SolutionsDocumentation software developer Wiltshire 2001 94.96% 4,618 80 Software helps likes of Glaxo Smith Kline prepare drug documents
54 AvellinoData software developer Berkshire 2001 94.59% 4,623 16 Discovered client had an extra million customers in their database
55 GamCom SolutionsE-business software developer NW London 2001 93.80% 1,365 27 Three brothers build fantasy fund-management system for Norwich Union International
56 Spektra GroupE-business software developer Livingston 2001 91.32% 4,940 55 Founded after an MBO from Schindler, the Swiss multinational
57 TechnetixTelecoms equipment maker West Sussex 2001 89.49% 25,120 123 Recently outsourced 90% of production to China to cut costs
58 Mosaic SoftwarePayment software developer Surrey 2001 84.56% †7,228 149 Software used by 11,000 E*Trade machines to top up phone cards
59 Bell MicrosystemsIT services provider Portsmouth 2001 83.46% 2,547 7 Engineers hack into clients' networks to test security
60 CellTrackerTelecoms software developer Bedfordshire 2001 83.20% 2,237 25 Database software tracks mobile-phone masts for Nokia and Ericsson
61 Sports InteractiveComputer game developer North London 2001 82.85% 2,221 15 1,500 unpaid fans contribute to football management game
62 ePulseFinancial software developer Central London 2001 82.28% 1,071 14 Software is designed to detect rogue traders like Nick Leeson
63 VIS EntertainmentComputer games developer Dunfermline 2001 81.46% 3,566 113 Creates 'virtual horses' for digital TV gambling channel
64 Alpha Data Parallel SystemsElectronic systems designer Edinburgh 2001 81.43% 1,582 9 Computer processor will help power NASA's next Mars probe
65 Concept TelecomTelecoms services provider Nottingham 2001 79.55% 7,866 28 Helps Nokia and Sony Ericsson develop and test new products
66 Omitec GroupElectronic equipment maker Wiltshire 2001 78.76% 8,280 88 Uses F1 engine-testing technology to find faults on road cars
67 EDW TechnologyRetail software developer Milton Keynes 2001 78.29% 2,515 25 Helped Electricity Direct sell power to 72,000 business customers
68 Pulse Software SystemsFinancial software developer Surrey 2001 77.76% 1,045 16 Software helps fund managers and stockbrokers manage portfolios
69 Allpay.netElectronic payment provider Herefordshire 2001 76.52% 3,340 16 Former debt-collector develops national online payment network
70 Primal PicturesMedical information publisher Central London 2001 75.79% 1,596 34 Aims to produce the Gray's Anatomy for the 21st century
71 InferMedMedical software developer Central London 2001 74.28% 1,680 40 Software based on 10 years' research at Imperial Cancer Research
72 Micro-RoboticsElectronics designer Cambridge 2001 73.20% 1,438 13 Won a scientific and technical award at the 1992 Oscars
73 WaterstonsIT services provider Durham 2001 71.93% 2,002 39 Founder joined by husband to start company in their basement
74 Sense InternetWeb design agency Leeds 2001 71.17% 1,045 27 Former music producer builds websites for Rizla and British Airways
75 Quality PLUS ConsultingCall-centre software provider Flintshire 2001 70.95% 3,483 24 Founder sold house to set up high-tech company over kebab shop
76 Circle SystemsProperty software developer NW London 2001 67.69% 1,665 15 Personal software project grew into profitable business
77 ClinPhoneClinical trials processor Nottingham 2001 67.20% 8,791 150 Former doctors develop system to gather data from clinical drug trials
78 The Message PadCall-centre systems developer Warwick 2001 66.98% 4,105 160 Company answers clients' phones when they cannot
79 SynopticsScientific equipment maker Cambridge 2001 66.64% 6,051 47 Customers range from Nestlé to Vauxhall and the FBI
80 CSW GroupHealthcare IT provider Oxford 2001 66.30% 1,867 53 Meeting at bus stop leads to expansion into hospital software
81 1EEnterprise software developer West London 2001 65.91% 1,537 10 Company named after a Microsoft computer error
82 IVCAudio-visual systems integrator Yeovil 2001 63.30% 2,352 3 Recently won £2.1m IT project for London's new City Hall
83 CadcorpMapping software developer Stevenage 2001 62.84% 3,218 25 Digital-mapping software used for 2002 World Cup in Japan
84 SearchspaceFinancial software developer Central London 2001 61.02% 4,307 134 Claims its software monitors 200m financial transactions every day
85 Allan WebbElectronic document producer Gloucestershire 2001 59.61% 2,853 60 Develops software that turns printed documents into electronic files
86 PrometheanEducational technology developer Blackburn 2001 58.99% 16,400 135 Electronic whiteboard used by schools in 15 countries
87 Interactive SoftwareSoftware developer Birmingham 2001 58.86% 1,159 21 Software helps British Tourist Authority market Britain
88 Oakleigh ConsultingIT consultancy Manchester 2001 57.82% 2,008 16 Claims that 90% of turnover is repeat business
89 McLaren GroupRacing team and sports car maker Surrey 2001 57.61% 9,520 173 Company develops engineering software used by Bayer and BHP Petroleum
90 Eclipse InternetInternet service provider Exeter 2001 57.60% 2,124 25 Claims to be gaining 40 new customers a day
91 NetKonect CommunicationsInternet service provider Hampshire 2001 57.19% 5,093 40 Founder borrowed £150,000 to start company
92 Blitz GamesComputer games developer Warwickshire 2001 57.04% 5,547 92 Twin brothers write hit computer games for Warner Bros and Disney
93 SirocomTelecoms services provider SW London 2001 56.15% 6,376 32 Built network to connect STA Travel's 400 worldwide offices
94 Armstrong CommunicationsCall-centre software developer Manchester 2001 56.09% 1,827 22 Enables call-centre workers to work from home via the internet
95 Sibelius SoftwareMusic software developer Cambridge 2001 55.97% 3,351 50 Oxbridge twins' software used at Queen's jubilee concert
96 SophosSecurity software developer Oxfordshire 2001 55.33% 22,625 198 Tackles more than 500 new computer viruses every month
97 NetservicesInternet service provider Manchester 2001 53.52% †1,948 18 Manages 90,000 e-mail accounts for troubled Tyco International
98 Synergy Software SolutionsFinancial software developer Luton 2001 52.45% 1,256 35 Former Financial Times partner becomes competitor
99 Insure-comInsurance software developer Brighton 2001 52.26% 1,719 34 Provides software in exchange for commission on insurance sales
100 EnsoftNetwork software developer Hertfordshire 2001 52.10% 2,838 26 Hires predominantly Oxbridge graduates to write software for Cisco

* supplied by company  † annualised figure