Principles into Practice 21 21 21 21
If the AI-enabled system did not work as intended, what is the worst thing that could happen?
Filed under:
Bias and Harm Mitigation

A worst-case scenario test for AI refers to stress-testing an artificial intelligence system under extreme, high-risk, or failure-prone conditions to assess its limitations, vulnerabilities, and potential negative consequences. This approach is particularly relevant for ensuring AI safety, reliability, and alignment with ethical and security principles, such as those outlined in the UK Ministry of Defence's (MoD) Responsible AI Principles. See cards: Measuring Reliability: how do we decide if an AI system is “suitably” reliable?, Measuring Robustness: how do we decide if an AI system is “suitably” robust?, Measuring Security: how does one decide if an AI system is “suitably” secure?.
 
  1. Worst case testing 
  2. Types of worst case scenarios 
  3. Measuring the scale of potential harm? 
 
1. Worst case testing
The goal of worst-case testing is to identify risks that might not be apparent in normal operating conditions. These tests help in:
• Preventing catastrophic failures in critical systems (e.g., defence, healthcare, finance, and autonomous vehicles).
• Understanding unintended consequences, such as biases, security breaches, or unpredictable decision-making.
• Evaluating how AI behaves in extreme or adversarial situations.
 
 
2. Types of worst case scenarios
The types of Worst-Case Scenarios for AI in a military context vary, but could include:
1. Adversarial Attacks – Testing AI against deliberate attempts to manipulate or deceive it, such as misleading inputs in machine learning models (e.g., adversarial examples in image recognition).
2. Ethical Failures – Examining how AI responds to morally complex situations, such as prioritising human lives in autonomous vehicle crashes.
3. Data Poisoning – Assessing the impact of biased, corrupted, or incomplete data on AI decision-making.
4. Operational Failures – Simulating real-world stress conditions where AI systems might fail (e.g., loss of internet connectivity for AI-driven infrastructure).
5. Human-AI Interaction Risks – Evaluating scenarios where AI misinterprets human intent, leading to dangerous or unintended actions (e.g., AI misidentifying a target in a military context).
6. Runaway AI Scenarios – Stress-testing self-learning systems for risks related to autonomous goal misalignment (e.g., AI optimising for efficiency at the expense of human safety).
 
 
3. Measuring the scale of potential harm
When trying to measure the scale of the potential harm, it is useful to consider the impact and the risk. Although it would be easy to assume that lethal autonomous weapon systems (LAWS) would automatically be at the far end of the spectrum of harms if something goes wrong, a strategic level decision made by a person that is informed by erroneous or false recommendations by a trusted AI-enabled system could have far greater ethical impact than any single action by a LAWS.
Worst-case scenario testing is an essential aspect of AI safety and ethics, particularly in defence and security applications. By rigorously assessing how AI responds under extreme conditions, as well as thinking through worst-case scenarios, policymakers and developers can mitigate risks, ensuring AI serves human interests while aligning with ethical and legal frameworks.

Disclaimer

This tool has been created in collaboration with Dstl as part of an AI Research project. The intent is for this tool to help generate discussion between project teams that are involved in the development of AI tools and techniques within MOD. It is hoped that this will result in an increased awareness of the MOD’s AI ethical principles (as set out in the Ambitious, Safe and Responsible policy paper) and ensure that these are considered and discussed at the earliest stages of a project’s lifecycle and throughout. This tool has not been designed to be used outside of this context. 
The use of this information does not negate the need for an ethical risk assessment, or other processes set out in the Dependable AI JSP 936 part 1, the MODs’ policy on responsible AI use and development. This training tool has been published to encourage more discussion and awareness of AI ethics across MOD science and technology and development teams within academia and industry and demonstrates our commitment to the practical implementation of our AI ethics principles.