Theseus is a clinician-led threat assessment practice.

We advise individuals, organisations and brands that find themselves the focus of intrusion, harassment, threats or persistent and unreasonable complaint.

We provide assessment, resolution planning, advocacy and training services to reduce or remove the human, financial and reputational impact of these fixated behaviours.

Unique pedigree. Unique experience. Unique focus.


We specialise in written and uttered communication that is worrying, threatening or bizarre, received by:

Phone calls
Face-to-face or shouted communication
Social media posting


We advise and help manage cases involving:

Loitering at home, at work or on route between them
Accosting in public or private
Entering the home or work place
Disruption of public or private events


We advise on cases involving a range of behaviour associated with unwanted communication and contact, including:

Online hate or justice campaigns
Cyber-stalking / controlling a victim’s computer or impersonating online
Unconditional / conditional threat
Direct / indirect threat
Work place bullying, violence and stalking
Property damage
Insider activity
Vexatious complaint
Vexatious litigation and whistle-blowing
Disgruntled former employees
Lone-actor violence

  • The resolution of problems involving idiosyncratic, threatening, obsessive or vexatious quests is seldom ever as binary as taking immediate legal action. Indeed, doing so without psychological consideration of likely outcomes has caused some of the most acute and persistent cases on which we have advised. Understanding motivation, state of mind and psychological responses are key to lowering risk and achieving safety, reputational or business objectives. – Dr David James MBBS, MA, FRCPsych
    Theseus Partner and former Clinical Director for the Fixated Threat Assessment Centre

  • While the individual man is an insoluble puzzle, in the aggregate he becomes a mathematical certainty. You can never foretell what any one man will do, but you can say with precision what an average number will be up to.– Sherlock Holmes, The Sign of Four, 1887