The ability required to make a particular decision at a particular time under the applicable legal test.
Back to the glossaryConsent & relationships
Capacity to consent
The present, decision-specific ability to understand relevant information, use or weigh it and communicate a choice. The exact legal test depends on the UK jurisdiction and context.
Consent & relationships
In brief
A present ability to choose—not a label attached to a person.
Capacity is about whether a person can make the particular decision at the relevant time—not whether somebody else approves of it. Sleep, unconsciousness, severe intoxication, acute confusion or some effects of illness may remove capacity, while disability or diagnosis alone does not.
Whether force, threats, coercion or other constraints prevent a genuinely free choice.
The actual agreement made by choice where the person has the required freedom and capacity.
How a choice is expressed; speech is not the only possible method, and support may be needed.
Decision- and time-specific
Capacity should not be inferred globally from age, disability, mental-health diagnosis, communication style or an unwise decision. A person may have capacity for one decision and not another, or capacity may fluctuate.
Information and communication should be made accessible before concluding that someone cannot decide. Extra time, plain language, interpretation or communication aids may support the person's own choice.
Sexual-offence law
In England and Wales, section 74 of the Sexual Offences Act 2003 refers to agreement by choice with freedom and capacity to make that choice. Scotland defines consent as free agreement under a separate statute, and Northern Ireland has its own framework.
Age-specific and protective offences can apply regardless of apparent agreement. A general capacity explanation therefore cannot establish whether a particular sexual act is lawful.
Intoxication, sleep and consciousness
A person who is asleep or unconscious cannot make a current sexual decision. Intoxication is fact-specific: drinking does not automatically remove all capacity, but severe intoxication may do so well before complete unconsciousness.
An earlier plan does not authorise activity after capacity is lost. The safe response to doubt is to stop and wait until the person can make and communicate a clear choice.
Support and safeguarding
Supporting decision-making means helping the person understand and express their own will, not obtaining the answer another person wants. Dependence on care can also create freedom and safeguarding concerns separate from capacity.
Healthcare, adult-protection and sexual-offence law use related but not identical tests. Professionals should apply the correct statute and local procedure.
Non-graphic examples
What the umbrella may include
- Waiting until a sleeping person is awake before proposing anything.
- Using plain language and a communication aid.
- Recognising that severe intoxication may prevent a meaningful decision.
- Assessing the specific decision rather than assuming incapacity from disability.
- Stopping when acute confusion makes the person's wishes unclear.
Reviewed 30 August 2026
Keep exploring.
This detailed field note uses the best available evidence without treating one community sample as universal. Evidence limits and UK context are stated where relevant.
Prepared by The UK Kink Guide editorial team. Read the evidence and review methodology.
Found an error or important omission? See how to report a correction.
Explore all 268 entries