## Facts

- Collins climbed a ladder to an open bedroom window where a young woman was sleeping.
- He initially appeared at the window, then descended, removed most of his clothing except for his socks, and climbed back up.
- The woman, mistaking Collins for her boyfriend, invited him inside; sexual intercourse ensued.
- Collins was subsequently charged with burglary with intent to rape, with the prosecution arguing that his presence at the window amounted to entry.

## Issues

1. Whether Collins’s entry at the window constituted “entry” sufficient for a burglary conviction under section 9(1)(a) of the Theft Act 1968.
2. Whether the entry was both “effective” and “substantial,” as required by law.
3. Whether Collins’s entry was as a trespasser, given the woman’s mistaken invitation.

## Decision

- The Court of Appeal held that for burglary, "entry" requires both effectiveness and substantiality, not merely minimal or temporary presence.
- Entry must directly enable or relate to the commission of the intended crime.
- The court found that an invitation induced by a mistaken belief as to identity does not prevent the entrant from being a trespasser.
- The standard for determining "effective and substantial entry" depends on the facts of each case and is a matter for the jury.

## Legal Principles

- For burglary, entry must be both effective (enabling the crime) and substantial (more than minimal or fleeting).
- Presence at a window alone, without more, may not constitute sufficient entry.
- The status of trespass depends on whether the occupant’s consent was valid; mistaken identity can vitiate true consent.
- The jury must decide whether the circumstances amount to effective and substantial entry as a trespasser.

## Conclusion

R v Collins clarified that a conviction for burglary requires proof of an “effective and substantial” entry by the defendant as a trespasser, and that an apparent invitation based on mistaken identity does not legitimize the entry if the consent in question is invalid. This judgment solidified fundamental evidential standards that continue to define burglary under English law.

R v Collins [1973] QB 100