Three tiers: Tier 1 (£52 / £40 by direct debit) for micro-organisations under 10 staff and £632,000 turnover; Tier 2 (£78 / £66 DD) for small and medium; Tier 3 (£2,900) for large. Some are exempt (judicial functions, personal/household activities). Failure to register is a strict-liability civil offence with a fixed penalty up to £4,350. Most businesses tick the box when filing their confirmation statement — the two registers should always match.