Plain-English guides to UK Corporation Tax and CT600 filing.
HMRC charges escalating penalties for late CT600 filing, starting at £200 for filing dates on or after 1 April 2026. Here's exactly what happens, how to avoid penalties, and what to do if you've already missed the deadline.
Late CT600 filing penalties explained: from 1 April 2026, £200 on day one and £400 at 3 months — doubled from previous rates. Plus 10% tax-geared penalties and 7.75% late payment interest. How to minimise the damage.
Complete guide to HMRC penalties for Corporation Tax — late filing (from £100 fixed, rising to £200 for deadlines from April 2026, plus up to 20% of unpaid tax), late payment interest, and inaccuracy penalties. How to avoid them.
HMRC's free CT600 service closed on 31 March 2026. Step-by-step guide to filing your corporation tax return from April 2026 using commercial software.
Miss your CT600 deadline and HMRC charges escalating penalties — from £200 on day one for filing dates from April 2026, rising to 10% of unpaid tax. Learn the full penalty structure, appeal options, and how to file on time.
Missed your CT600 deadline? Learn the exact HMRC penalty structure — £200 initial then 10% and a further 10% for filing dates from April 2026 — how late payment interest works at 7.75%, and the steps to fix it fast. Plus how to appeal.