Management Team

David McGuire
Chief Executive

While studying for a teaching degree at the University of Córdoba, at the age of 18 David set up his own company which was dedicated to the provision of health and safety services to different communities.

David joined Diagrama on leaving university and spent his first five years as a Social Educator in a secure establishment for the Diagrama Foundation in Spain, also achieving his Social Educator Degree during that time. In 2006 he led an after-care programme which helped over 400 children and young people who had been through the justice system.  He established links with all the relevant community agencies and organisations which support the young people to reintegrate into society.

In 2008 he moved from Spain to the UK with his family to establish the Foundation in the UK and was appointed Chief Executive in 2009.David is m ember of the European Society of Criminology (ESC) and the European Prison Education Association (EPEA). In 2019 he was awarded his Professional Doctorate in Children & Young People’s Services Leadership from the University of Bedfordshire.

Derek Milliken
Chief Operating Officer

Derek brings to Diagrama over 26 years’ experience in a variety of sectors, the most recent of which have been as a senior executive in a FTSE 100 global organisation.

His main career focus has been in the custodial sector, where he project managed the operational mobilisation of a large new build custodial centre, going on to successfully run this and an adjoining establishment. During that time he was able to negotiate a contract extension which delivered improved margins for the business whilst delivering significant savings for the customer. He was also instrumental in delivering staff efficiencies through improved retention rates and strong absence management procedures.

Derek has overseen the robust statutory inspection requirements which are set by various regulatory bodies such as Her Majesty’s Inspectorate of Prisons, Ofsted and the Care Quality Commission and was proud to share with his team the achievement of external accreditation from Investors in People and the British Safety Council 5 Star Award, International Award, Sword of Honour.

As a contract director, Derek oversaw the delivery of 24 hour Primary Healthcare Services including GP clinics, nurse clinics and emergency response, mental health, dentistry, optician and various other health and well-being related services.

Derek has significant experience of building and maintaining customer and stakeholder relationships, in particular with public sector clients, and also brings extensive insight, knowledge and experience of cultural, social and health issues and challenges in complex environments.

Derek is responsible for the day-to-day management of Diagrama's UK operations.

Helen Dean
Head of Professional Standards and Business Development

Helen joined Diagrama in 2017, with over 25 years’ experience working in the public sector in project and other management roles.

Helen’s early career was with the Metropolitan Police Service (MPS) as a project manager and internal consultant working on areas as diverse as development and evaluation of new policing policies, MPS corporate strategy development and roll-out of new IT systems. She then joined the MPS’s Performance Information Bureau leading projects to implement new data and management information systems.

In 2009 she joined the Youth Justice Board (YJB) for England and Wales, heading up the governance team to lead the YJB’s business planning, reporting and risk management processes, and then from 2012 leading major projects on behalf of the YJB.

She has experience in programme and project management, group decision-making, business analysis, business case development and strategy development.

At Diagrama, Helen is responsible for business development, project and tender management and professional standards.

Mary Collier
Head of Legal

Mary has spent the past 10 years in private practise, and is currently a partner in a central London firm where her work extends over a broad range of commercial matters including residential and commercial property, company and intellectual property.

Over recent years she has expanded her firm's charity practise, driven mainly by her interest in community and social welfare. It was therefore a natural step when in 2015 she took on the role of in-house counsel for Diagrama Foundation.

At Diagrama Mary looks after all the legal and business affairs needs for the charity and its subsidiary trading companies, as well as governance and compliance. She splits her time between Diagrama in Rochester and her firm's offices in central London.

Richard Dunn
Head of HR

Richard is a highly innovative commercially aware HR professional who has a wealth of experience within all aspects of people management at strategic and operational levels spanning a career of 40 years in the public and latterly private sector.

His experience covers all major sectors within a custodial environment, including prisons, police services, immigration and children’s services.

His recent achievements include supporting the operational mobilisation of a large new build custodial centre involving significant recruitment and training and employee engagement initiatives; leading the HR aspects of a variety of acquisitions involving TUPE and supporting the operations in achieving QA and Investors in People external accreditation.

Richard has significant experience of implementing change within organisations and supports the operations in driving through people management issues ensuring best practice is championed within the organisation.

Julie Firth
Head of Marketing and Communications

Julie is an award-winning, multi-skilled communications professional. She has previously worked as marketing design manager for Express Newspapers and later as a senior multimedia journalist at the Press Association.

Prior to joining Diagrama in 2015 she was responsible for all PR, marketing and communications for a thriving children’s cancer charity.

Julie has extensive experience of publication editing and design, social media management, web content management, internal and external communications, campaigns, publicity, press relations and marketing. She is responsible for the development and implementation of the marketing and communications strategy for the Diagrama Foundation across all areas of its work - encompassing internal communications, management of social channels and all PR activity.