Assault by penetration is treated by the law as seriously as rape. It carries a maximum sentence of life imprisonment and can only be tried in the Crown Court. Allegations often arise between people who know each other, after a night out or within a relationship, and usually turn on the question of consent.
If the police have contacted you
- Do not attend a police interview, voluntary or after arrest, without a solicitor.
- Free legal advice at the police station is your right, whatever your income.
- Do not contact the person who made the allegation.
- Do not delete messages, photos, apps or social media accounts.
- Do not discuss the allegation with anyone other than your solicitor.
What is assault by penetration?
Under section 2 of the Sexual Offences Act 2003, a person commits assault by penetration if they:
- intentionally penetrate the vagina or anus of another person with a part of their body or anything else,
- the penetration is sexual,
- the other person does not consent, and
- they do not reasonably believe that the other person consents.
Any degree of penetration is enough. Where the complainant is under 13, the separate offence of assault of a child under 13 by penetration applies under section 6, and consent is irrelevant.
Consent and reasonable belief
Most cases turn on consent. Section 74 says a person consents if they agree by choice and have the freedom and capacity to make that choice. Your belief in consent must be reasonable, judged on all the circumstances, including any steps you took to find out. The law presumes there was no consent in some situations, for example where the complainant was asleep or unconscious, unless there is evidence to the contrary. Read our guide to consent in UK sexual offence law.
The investigation
The police will usually arrest you or invite you to a voluntary interview, and may seek forensic samples, clothing and your phone. The complainant may have been examined at a sexual assault referral centre. Before your interview, a solicitor will get disclosure and advise you on how to respond. See our guide to police interviews for sexual offence allegations. Afterwards you are likely to be bailed or released under investigation while the CPS considers a charge: see released under investigation.
Possible defences
- Consent, or reasonable belief in consent, based on what was said and done, previous communications and the relationship between you.
- No penetration: the act alleged did not happen, or did not involve penetration, which may mean a lesser offence such as sexual assault at most.
- Not sexual: for example, a genuine medical or caring procedure.
- Identity: you were not the person involved.
- The allegation is false: see defending false allegations.
Messages, social media, location data and the complainant's own digital records are often critical. The defence should press for full disclosure of this material. See our guide to digital evidence.
What sentence can you get for assault by penetration?
The maximum is life imprisonment. Under the Sentencing Council guideline, the offence range is a community order to 19 years' custody. The starting point for the most serious cases is 15 years, within a range of 13 to 19 years, while starting points for the least serious cases are much lower. The court considers the harm caused, such as severe psychological harm or violence beyond that inherent in the offence, and culpability, such as planning or the use of alcohol or drugs to facilitate the offence.
A conviction also brings notification requirements and often a Sexual Harm Prevention Order. See our guides to sexual offence sentencing and the sex offenders register.
Going to court
After charge, the case goes to the Crown Court for a plea and trial preparation hearing, and then to trial if you plead not guilty. Questions about the complainant's sexual history are restricted and need the court's permission. Our court representation page explains each stage, and our rape defence page covers the closely related procedure in rape cases.
Frequently asked questions
What is the difference between rape and assault by penetration?
Rape requires penetration with a penis. Assault by penetration covers penetration of the vagina or anus with any other part of the body, such as fingers, or with an object. Both carry a maximum of life imprisonment and are tried only in the Crown Court.
Can a woman be charged with assault by penetration?
Yes. Unlike rape, assault by penetration can be committed by anyone, regardless of sex.
Will the case go to the Crown Court?
Yes. Assault by penetration is an indictable-only offence. After a first hearing at the magistrates’ court, the case is sent to the Crown Court, where a trial takes place before a judge and jury if you plead not guilty.
Will I be on the sex offenders register?
A conviction for assault by penetration brings notification requirements. Their length depends on the sentence: a sentence of 30 months or more means indefinite notification, with the possibility of a review after 15 years.
Is there a time limit for an allegation?
No. There is no time limit for prosecuting assault by penetration. Allegations relating to events before 1 May 2004 are usually charged as indecent assault under the Sexual Offences Act 1956.
How we help
We are a referral service, not a law firm, and we do not give legal advice ourselves. When you contact us, we pass your details in confidence to an independent solicitor who specialises in sexual offence defence, so they can contact you directly. We cover the whole of England and Wales, including London, Manchester, Birmingham, Leeds and every other area we cover.
This page is general information about the law in England and Wales, not legal advice. Last updated 11 November 2026.