Crown Security Services based in Brimingham offers a range of services, such as manned guarding, CCTV remote monitoring, keyholding & alarm response, mobile security patrols & construction site security. Crown Security Services provide an off-site CCTV monitoring and protection service for commercial, industrial and residential premises through the use of remote digital technology, cameras and motion activated CCTV systems.

CSG UK PLC specialise in the installation, maintenance and support of security systems for companies and organisations throughout the UK and Europe. CSG UK supply and install comprehensive security systems for national chains and individual businesses in the form of: CCTV, Access Control, Public Address, Intruder Detection and EAS (Electronic Article Surveillance), Fire and Safes.

CSM specialise in support service facilities management solutions for the Construction & Commercial Property sectors. They offer services such as physical security, CCTV security, mobile security, cleaning services and many more.

For more than 10 years, Cube security has been in the business of installing security products such as fire alarm, intruder alarm, CCTV and access control equipments.

Established in 2005, Cultris Security Systems Inc. is a full-service fire, security, access control, video and communications company. They specialise in intrusion detection, access control, and video surveillance systems for commercial and residential customers.

CY4OR is a global services firm providing extensive knowledge and expertise in digital forensics, edisclosure and information security.

CyNam is a Community Interest Company based in Cheltenham, the cradle of UK cyber innovation. The goal of CyNam is to bring together the best technology minds from local SME’s and Startups to fully harness the rich cyber security ecosystem that flourishes around Cheltenham, the home of the National Technical Authority for Information Security, GCHQ.

D-Fence Electronic Fencing and Security Systems Ltd. is an Israeli "Security-by-Technology" company that designs, develops and manufactures the most advanced Perimeter Intrusion Detection Systems (PIDS), based on an exclusive Strain Gauge Sensor technology. This proprietary technology allows us to offer highly aesthetic PIDS based on the “Open-Design” concept, and most importantly, that work with Zero False Alarms.

D & A Systems is an engineering company, providing electrical and specialist services to industry and commerce. The company offers electrical engineering services, high voltage construction and maintenance, electrical testing and inspection, quality power management, public address & voice alarm systems, CCTV & access control systems, and data network structured cabling.

D&D Security Derby offers fully licensed SIA-approved security guards that are ready to be deployed within hours upon acceptence. It provides approved contractor security services for major companies across the UK. Specialists in static guarding, it offers a cost-effective security service for the protection of UK businesses.

DA Security Systems are a family run CCTV, Fire and Alarm Business. It has been operatiing from Lee-on-the-Solent in Hampshire, UK since 1984. It has over 40yrs experience with the installation and maintenance of CCTV, Fire Alarm, Intruder Alarm, Door Entry and Nurse Call systems.

Dante provides project management services as well as commercial fire and security systems throughout the UK. The company has mechanical and construction divisions. Dante has achieved the quality standard ISO9001 and environmental standard ISO 14001. The company's specialisms include CCTV, door entry, intruder alarms, fire safety, and PA/VA.

DAS Technology can design, install and maintain security systems for a wide range of uses from homes, shops and offices to shopping centres, schools and car parks. They provide bespoke security solution that meets your needs, and all completely hassle free. Their nationwide network of engineers is trained to the highest standard in order to install security systems with a professional, efficient and reliable service.

Dassault Aviation is a French aerospace, defence equipment and security systems company that shapes the future by designing and building military aircraft, business jets and space systems. They expertise as a manufacturer of both military aircraft and business jets. Creator of more than 100 prototypes in the last century, with over 10,000 aircraft delivered to 90 countries.

DataCore parallel I/O and virtualisation technologies deliver the advantages of next generation enterprise data centres by harnessing the untapped power of multicore servers. DataCore software solutions revolutionise performance, cost-savings, and productivity gains businesses can achieve from their servers and data storage.

UK based Datasat Communications delivers remote communication solutions for governments, commercial organisations, and emergency services. Datasat designs and builds networks that deploy combination of satellite, wireless and fibre communication technologies to precisely meet business requirements. Datasat provides multi-site security, remote asset protection, perimetre security & access control, and traffic management.

Datastor integrate the best in proprietary equipment and software products to provide not only the optimum solutions to their clients individual needs but also one which communicates seamlessly with other key applications.

DC Solutions is a CCTV installer based in Luton.

de Jong SICHERHEIT & IT GmbH is an innovative system house for security, information and network technology and develops, among other things, intelligent solutions for hygienic access to buildings and rooms.

With more than 100,000 professionals, Deloitte provides audit and assurance, tax, consulting, and risk and financial advisory services to a broad cross-section of the largest corporations and governmental agencies.

Denning Electronics has solved big communications, protection, and surveillance problems by providing sales and technical support to distributors, security system integrators, engineering design firms, architects, and system users. Their specialties include outdoor intrusion detection, video and audio surveillance, video/audio/data networks and transmission, access control, and ballistic/blast/chemical/acoustic barriers.

Detection Security Systems offers complete range of specialist electronic fire & security systems to meet the ever changing needs of residential, commercial, retail and industrial clients. The company provides products and services such as intruder alarms, CCTV systems, access control, fire alarms, alarm monitoring, gate automation as well as service and maintenance.

Detectortesters is a designer and manufacturer of testing technology for fire detection systems. In-house expertise across a range of technical disciplines means they are able to constantly innovate and develop new technology to bring new ideas and solutions to both users of their products and anyone with a responsibility for fire safety.

Diamond Security Systems (UK) Ltd is a specialist CCTV design, installation and maintenance company.

Through their 24/7 Security Operations Centre, DigitalXRAID delivers cyber security strategies to organisations that enhance the security posture and reduce the risk, cost, and reputational damage of a breach.