You do not have to answer police questions. You can say "no comment" and it cannot usually be used to suggest guilt on its own — though in some circumstances staying silent can affect a later defence. A solicitor can advise you on this before you're interviewed.

Free and independent legal advice is available at the police station whether you can afford it or not — from a duty solicitor or one of your choosing. You can ask for this at any point. It's usually worth taking, even for a "quick chat."

You can ask police to tell one named person where you are. This may be delayed only in limited, serious circumstances, and you must be told if that happens.

Police can normally hold you for questioning for up to 24 hours before charging you or releasing you, extendable by a senior officer up to 36 hours, and beyond that only with a magistrates' court warrant (up to 96 hours) for indictable offences. Under terrorism powers, different limits apply.

Give your name, address, date of birth and nationality when asked — this is usually required. Beyond that, you're not obliged to explain yourself before getting legal advice. Stay calm, keep your hands visible, and don't resist physically even if you disagree with what's happening — challenge it afterwards, through a solicitor or complaint.