CT600 Filing Agent Authorisation with HMRC
How to authorise an agent to file your CT600. Step-by-step guide to HMRC agent authorisation for corporation tax — online, by post, and what to do if things go wrong.
Plain-English guides to UK Corporation Tax and CT600 filing.
How to authorise an agent to file your CT600. Step-by-step guide to HMRC agent authorisation for corporation tax — online, by post, and what to do if things go wrong.
Find the most tax-efficient director salary for 2025/26. We explain the NIC thresholds, employer costs, and how to save thousands through your limited company.
Which expenses can't you deduct on your CT600? Complete guide to disallowable expenses for corporation tax — entertaining, fines, personal costs, and more.
How the Flat Rate VAT Scheme affects your corporation tax. Learn about the VAT surplus, how to report it on your CT600, and whether the scheme still saves money.
How long does an HMRC corporation tax refund take? Typical timescales, what causes delays, how to chase a late repayment, and tips to get your refund faster.
What are the penalties for filing your CT600 late? Understand HMRC penalty rates, interest charges, and how to avoid or appeal late filing penalties.
Complete guide to allowable limited company expenses for Corporation Tax. Covers office costs, travel, staff, professional fees, and what HMRC disallows.
How employer pension contributions reduce your CT600 corporation tax bill. Limits, timing rules, and how to claim the deduction for your limited company.
How UK small and medium-sized companies can claim R&D tax credits. Covers eligibility, qualifying costs, calculation examples, the merged scheme, and how to include R&D relief on your CT600.
CT600 vs annual accounts: one goes to HMRC, one to Companies House. What each is, when they are due, and how they relate.
File your CT600 without an accountant in 2026. What you need, how to prepare accounts, calculate tax, and submit to HMRC.
HMRC charges interest on late corporation tax at base rate + 4% — currently 7.75%. Learn current rates, how interest is calculated, and how to avoid it.