2.2 Necessity, Proportionality and Reasonable Force

2.2 Necessity, Proportionality and Reasonable Force

Quick Answer: You may use force only when it is necessary (no lesser option reasonably available), proportionate to the threat and harm to be prevented, and reasonable in the circumstances as you honestly believed them to be. Always prefer the least restrictive option that works, and stop when the threat ends.

Section 2.1 explained when the law may authorise force. This section explains how much force may lawfully be used. Examiners constantly test necessity, proportionality, and reasonableness because most real complaints and criminal cases turn on excess, not on whether some intervention was ever allowed.

The three interlocking tests

Think of lawful force as three gates. All three must open:

These ideas appear in training language (last resort, dynamic risk assessment, graduated response) and in legal language (reasonable force). Learn both sets of words; they describe the same professional standard.

Necessity — no lesser alternative reasonably available

Necessary does not mean “convenient” or “quickest for the queue”. It means physical force was needed because other options could not reasonably deal with the situation.

Before or instead of force, consider:

1. Presence and positioning — open stance, safe distance, exit routes for you and them
2. Communication — clear requests, calm tone, explanation of consequences (“You need to leave now or we will call the police”)
3. Time and space — give a moment to comply when safety allows
4. Help and resources — extra colleagues, supervisor, police, medical help
5. Environment control — close a door, stop entry, move bystanders, cut music if it helps communication

If a person is already walking out after a verbal request, further physical contact is rarely necessary. If two people are trading punches, some physical separation may be necessary now — standing back and only talking may not protect anyone.

Necessity is dynamic. What was necessary at second one may not be necessary at second thirty. Reassess continuously.

Proportionality — not excessive to the threat

Proportionate force matches the seriousness of the threat and the harm you are trying to prevent.

Proportionality is about risk of harm, not about your anger, the customer’s insults, or “sending a message”. A spit or shove can feel personal; the law still asks whether your response matched the threat, not your frustration.

Property-only risks usually justify less force than risks to people. Recovering a stolen drink is never a reason for a headlock that compromises breathing.

Reasonable force and honest belief

The classic formulation is that force must be reasonable in the circumstances. Two linked ideas matter for security staff:

1. Subjective belief about the circumstances

You are judged by reference to the facts as you honestly believed them to be. If you honestly believed a glass bottle was about to be used as a weapon, that belief frames the situation — even if it later turns out the bottle was empty and the person was only gesturing.

Honest belief is not a free pass for fantasy. Training, lighting, alcohol, noise, and stress affect perception, but inventing a threat after the event will not protect you.

2. Objective reasonableness of the response

Given that believed situation, was the level and type of force something a reasonable person could use? Honest fear of a shove does not make repeated punches after the person is on the floor reasonable.

So the exam-friendly summary is:

Honest belief about the circumstances + objectively reasonable response to those believed circumstances.

You are not required to measure force with scientific precision in a split second. Courts and investigators recognise that decisions are made under pressure. What they do not accept is clearly excessive or prolonged force once control is achieved.

Graduated force and the least restrictive option

SIA physical intervention training emphasises non-pain compliance and low-level techniques. That design matches the legal expectation of the least restrictive option that is still effective.

A practical graduation model:

1. Primary controls — good venue design, entry standards, communication, early intervention before violence starts
2. Secondary controls — verbal de-escalation, warnings, offering choices, calling police
3. Defensive physical skills — protect yourself from blows, disengage from grabs (not the same as taking someone to the ground to punish them)
4. Non-restrictive prompts and guides — open-hand guidance, steering toward an exit
5. Low-level restrictive holds / escorts — standing holds as taught, preferably with a colleague
6. Higher-risk interventions — only if the threat justifies them; maximise medical monitoring; disengage as soon as safe

Skip steps only when the threat makes intermediate options unrealistic. Jumping straight to restrictive holds because you are impatient fails necessity and proportionality.

When the threat ends, the force must end

Legal justification is time-limited. Force may be reasonable to stop an assault; the same force becomes excessive when:

• The person is compliant and under control
• The fight is broken up and parties are separated
• The person is leaving as requested
• Police have taken over and do not need your continued restraint

Common over-force errors on the door:

• “Last shove” out the door after compliance
• Kneeling on the torso or neck area after resistance stops
• Pain to make someone apologise or hand over a phone number
• Restraint continuing for conversation or ID checks when standing talk would do
• Multiple staff piling on when two could hold safely

Punishment is never lawful self-defence or crime prevention. If the purpose is payback, the force is unlawful even if the person earlier committed an offence.

Worked venue scenarios

Scenario A — queue dispute

A customer in the queue becomes loud and abusive after being refused entry for intoxication. They stand still, hands visible, no advance on staff. Colleague wants to “spin them away” physically.

• Necessary? Not yet — communication, firm refusal, ask to leave, supervisor, police if they refuse and obstruct.
• Proportionate physical start? No. Physical contact for pure verbal abuse without imminent violence is hard to justify.
• Reasonable path: clear words, space, CCTV awareness, document, do not block them into a corner.

Scenario B — fight on the dance floor

Two customers exchange punches. Others start to film and crowd in. You and a colleague move in, use voice to order stop, separate the pair with low-level holds, move one toward a fire exit route, radio for support and first aid if needed.

• Necessary? Yes — crime in progress; people at risk.
• Proportionate? Standing separation and escort are aligned with training; avoid strikes unless defending against ongoing blows.
• When to stop? When separated, no longer assaulting, and either leaving, held pending police, or calmed under observation — not after an extra “reminder” shove.

Scenario C — theft with flight

Someone snatches a handbag and runs for the exit. You block the doorway with your body and shout to stop. They collide with you; you hold their arm and call colleagues and police. You do not chase into a dark car park alone or apply a neck restraint.

• Necessary? Some intervention to protect the victim and prevent escape of an offender may be justified if safe.
• Proportionate? Arm hold and containment differ from striking or dangerous ground pins for property crime.
• Belief: You honestly saw a theft; response stays aimed at stop-and-hold for police, not punishment.

Scenario D — over-force after spit

A ejected customer spits at a door supervisor. The supervisor punches them twice after they are already being walked away by two other staff.

• Original ejection may have been lawful.
• The punches after control are not necessary or proportionate; they look like retaliation.
• Criminal assault, civil claim, dismissal, and SIA action are all realistic outcomes.

Over-force consequences (preview of 2.4)

Using more force than the law allows can lead to:

• Criminal investigation (assault, battery; in worst cases more serious offences)
• Civil claims for personal injury and related losses
• Human rights scrutiny where state-linked or serious ill-treatment is alleged
• Employment discipline or dismissal
• SIA licence suspension or revocation and difficulty working in the industry again

“I was only doing my job” is not a defence to excessive force. Doing your job means staying inside the law.

Practical decision checklist (use under pressure)

Ask, as fast as the situation allows:

1. What is the threat to people (or property) right now?
2. What have I already tried that is less restrictive?
3. What is the minimum physical option likely to work?
4. Can I get a colleague so we use safer team techniques?
5. Am I still within my honest belief of the facts — or am I reacting to ego?
6. Has the need ended so I should disengage or downgrade?

Write incidents up honestly afterwards: what you believed, what options you tried, what force you used, and when you stopped. Accurate reporting supports lawful practice and protects everyone involved.

Summary link to skills training

Your physical skills syllabus — stance, disengagement, non-restrictive prompts, low-level holds, escorts — exists to give you proportionate tools. The legal tests in this section decide whether and how far those tools may be used. Master both: techniques without law is dangerous; law without technique is incomplete for the role.