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.

Marina Rubio
Head of Professional Standards

Marina joined Diagrama in 2017, having moved to the UK from Spain where she had studied a degree in Psychology and MSc in Healthcare.

Since then, Marina has had a number of roles within Diagrama, first as a Support Worker working with adults with learning disabilities, then as Interventions Manager, introducing Montessori techniques into Diagrama's services, ensuring high standards of person centre care. Marina has also been involved on Diagrama's European projects researching and sharing best practice.

In 2020, Marina became a CQC Registered Manager at our Cabrini service in Bromley, and then later in 2021 took on management and responsibility for our Supported Living Service.

In Summer 2023, Marina became Head of Professional Standards leading on the provision of technical support to the operational businesses to ensure that a robust system is in place to meet contractual and regulatory requirements across Diagrama UK.

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 Chatham and her firm's offices in central London.

Kulbir Kaur
Head of HR

Kulbir Kaur was appointed Head of HR in January 2024, after working for us since 2022. With over 15 years’ experience in HR and management, Kulbir has a degree in Business Studies and HR Management and recently gained her level 5 CIPD Associate Diploma in People Management.

Responsible for over 220 employees across our organisation, Kulbir has amassed a great working knowledge of the charity, now leading a robust HR team at Diagrama Foundation.

Tina Morris
Head of Marketing and Strategy

Tina Morris joined us in August 2023 after five years experience specifically within the Care sector at senior management level, and is a seasoned marketing professional with over 20 years experience in Marketing and Communications. She has worked on campaigns for FTSE 100 companies, within charities and not-for-profits and alongside local authorities.

Her passion lies in directing her marketing energy into charities that make a real difference. Having run her own business as well as developing marketing strategies for a host of organisations alongside running similar operations, her knowledge and skillset will assist Diagrama UK as part of the senior management team.