- Founded in 2009, Deep Secure is privately owned UK-based security software solutions firm. Services offered include Content Threat Removal, Content Transform, Policy Enforcement, Cyber Security, Data Security, Email Content Security, Web Content Security, Portal Protection and Deep Content Inspection.

Deister Electronic Ltd is one of the world's leading companies in the development, manufacture and marketing of electronic security and identification products.

Delaney Secure Ltd is an IT security distributor specializing in biometric authentication, door entry systems and PCI DSS compliance. Leading stockist of door entry solutions, time and attendance, fingerprint readers, palm vein readers, iris scanners, face recognition and OEM biometric hardware and software solutions.

Delta Tec Alarms delivers high-quality alarm systems and reliable alarms to customers. The company advises customers on the products that best serve their security needs.

Dent Security Systems is the Cambridge security specialist. Founded in 1870 by locksmith Robert Dent. The company offers integrated solution of electronic and physical security to meet any circumstances in home or business premises. The service includes installation and maintenance of residential & commercial ‘burglar alarm’ systems, intruder alarm, remotely monitored intruder systems, police monitored burglar alarms, CCTV/ Video surveillance.

Design Automator is a SaaS solution for the security systems industry that automates the engineering process, eliminates human error and delivers system wide consistency, whilst saving both time and money.

Destination 5 is a provider of access control, CCTV, intruder detection and advanced integrated Systems. The specialists work with government and public sectors is provided to support the foundation of our national infrastructure against security threat and to assist operative safety.

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.

Detego Global is the company behind award-winning Digital Forensics, Case Management, and Endpoint Monitoring solutions that are trusted by the military, law enforcement teams, intelligence agencies, and enterprises around the world. With the ever-increasing use of digital devices and the corresponding mass of data that are created, solutions have become the preferred choice for rapidly acquiring and analyzing.

DeterTech is an award-winning risk management company that uses proprietary technology-based solutions to deliver material cost savings for clients operating nationally in the infrastructure, construction, vacant property, and other sectors, across a range of security products and services.

Device Authority is a provider of Identity and Access Management (IAM) for the Internet of Things (IoT) and Blockchain. The Company also provides solutions such as data security, network access control, credential management and much more. Device Authority manufactures innovative smart, connected devices with robust security integrated from the outset.

Device Smart Ltd. have been developing Monitoring and Control Software & Middleware Platforms for over 15 years before cloud, before IOT, before "smart anything" was a buzz word.

DGS is managed and operated by this team who take a real hands on approach to all the operational aspects of each and every contract. DGS Service Solutions provide a range of outsourced Security, Cleaning and FM Solutions to a range of customers including shopping centers, offices, factories, and retail outlets.

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

Digital Barriers was established in 2009 to provide advanced surveillance technologies to the international homeland security and defense markets. The company brings innovative new thinking and solutions to the protection of most critical national assets, locations and infrastructure.

Digital ID specializes in all things ID and have stock from some of the biggest names in the industry. Digital ID is one of the leading providers of ID card printers from an array of respected manufacturers, including Magicard, Datacard, Evolis, Zebra and more. The company offers access control and smart cards, ID card and visitor systems, printable and printed ID cards, software, as well as accessories.

Digital Locksmiths Limited was founded by two former members of Smart Card Solutions: Sean Kelly & Martin Strauch. The Digital Locksmiths offer an unrivalled, independent capabiltity to help our clients provide the highly reliable, feature rich and cost effective products that customers demand.

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

Diligence BSB Forensic is one of the UK's leading independent Forensic service providers to the Police, Legal Profession, Corporate and Fraud Investigators. BSB assesses clients' CCTV systems or assists in purchasing decision or tender review, reporting in terms of systems ability to provide forensic material to be used in evidence. BSB Forensic offers a range of training courses covering forensic audio, video, document or fingerprint evidence.