Our services

All our services are designed to strengthen and improve the management of your organization. Allowing teams and individual managers to flourish, and providing assistance in finding the right people for the job. Our solutions are tailored to your specific demands and the characteristics of your organization.


A self-evaluation done right provides building blocks to further strengthen the board of management and/or the supervisory board. Not only non-executive boards but also executive teams can benefit immensely from a (periodic) evaluation.

Team evaluations are highly effective in shedding light upon the internal dynamics and the collaboration among team members. Indeed, much more than through individual performance reviews, a team based self evaluation provides insight and value.

Assessment & Leadership Audit

There are many situations that can call for objective second opinions on the quality of leadership. Whether it’s contracting a new manager, deciding on (executive) nomination, restructuring or charting and finding potential successors, Jonathan Warner’s assessments and audits will help you make the right decisions and will suit the demands of your organization.

Our executive assessments are always bespoke and personal by character.

Executive Coaching

The role of successful senior leaders often stretches beyond their job description – they are role models and sources of inspiration. However, they often have questions of their own to which answers are not easily found in their direct professional surroundings. Sometimes, it is not even about finding the answers to questions at all, but about finding a sounding board to discuss issues in the organization or matters of a personal nature.

Strengthening the executive team

Executive teams do not necessarily become winning teams by virtue of being composed of people with complementary competencies. The success of executive teams is just as much a consequence of stimulating exchange between their members. In top teams individual members stimulate one another and rise above their individual levels.

Executive collaboration

Effective cooperation in the executive layers of organizations is essential but not self-evident. Engagement and good intentions, however important, proof to be no guarantee for effective collaboration.

Differing perspectives, conflicting interests, unfortunate events or even details of governance can result in tensions which may hinder the effectiveness of the organization as a whole.

Leadership programmes

A leadership programme does much more than just developing individual leaders. An executive team that does a leadership programme strengthens its common sense of purpose and direction.

Also when larger groups of managers go through Jonathan Warner’s training programmes, not only quality of management will improve. It will have many positive effects on the organization, including its culture.

Council of Recommendation

  • Feike Sijbesma
    CEO and Chairman Managing Board Royal DSM, non-executive director at Unilever and De Nederlandsche Bank
  • Gerrit Zalm
    Former CEO and Chairman of the Board of Management ABN AMRO, non-executive director at Royal Shell and former minister of Finance
  • Hein Knaapen
    Chief HR officer ING. Adviser executive functions at Rijksoverheid (Central government)
  • Marike van Lier Lels
    Non-executive director at RELX (Reed Elsevier), TKH Group and NS Group. Former COO Schiphol Group
  • Rob ter Haar
    Non-executive director at Mediq, Ahold, VVAA group and Parcom Capital. Former CEO of Hagemeyer

Our team

Jonathan Warner has a team of 11 consultants. The qualifications of our team spread across the entire spectrum of our services. In addition, we maintain an extensive network of consultants whom we employ when the size or specificity of an assignment is beyond the capacity of the team presented below.
Arjan Eleveld

Arjan Eleveld

Managing partner and management consultant

Reinout van Kalleveen

Reinout van Kalleveen

Partner and executive coach

Amber van den Hout

Partner and assessment adviser

Herman Prakke


Dorien Gruppelaar

Dorien Gruppelaar

Assessment adviser and personal coach

Frank van Luijk

Frank van Luijk

Executive assessment adviser

Pernille La Lau

Presentation coach

Hans Roos

Management consultant and personal coach

Frédérique Groen-Dudok de Wit

Career consultant

Rene Bastiaansen

Specialist in leadership training

Frans Gosses

Frans Gosses

Executive coach

Jolanda Vollebregt

Office Manager

Contact details

Jonathan Warner
HNK, Oude Middenweg 17
2491 AC  The Hague

Jonathan Warner
+31 (0)6-347 35 201

Contact us