HMRC Free CT600 Filing Service Closed March 2026: What You Need to Do Now
HMRC closed its free Corporation Tax filing service on 31 March 2026. What this means for your company and how to file now.
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Plain-English guides to UK Corporation Tax and CT600 filing.
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Annual Investment Allowance (AIA): Claim £1M Tax Relief on Your CT600
How to claim Annual Investment Allowance on your CT600. £1 million limit, qualifying assets, how to calculate, and common mistakes.
What Is a UTR Number? How to Find Yours for CT600 Filing
Your Unique Taxpayer Reference (UTR) explained — what it is, where to find it, how it differs from your company number, and why you need it for CT600 filing.
HMRC Enquiry Into Your Corporation Tax Return: What to Expect
What happens if HMRC opens an enquiry into your CT600. Your rights, the process, time limits, and how to respond.
How to Pay Corporation Tax: Every Payment Method Explained
All the ways to pay your Corporation Tax to HMRC — bank transfer, direct debit, online, and by post. Processing times and payment references explained.
Small Company Corporation Tax Rate 2025/26: Everything You Need to Know
The small profits rate, marginal relief band, and how to check which rate applies to your company. Updated for the 2025/26 tax year.
Corporation Tax Payment: Deadlines, Methods & What Happens If You're Late
When to pay Corporation Tax, how to pay HMRC, payment reference numbers, and the consequences of late payment. Complete guide for limited companies.
Confirmation Statement (Annual Return): What It Is & How to File
Guide to filing your Companies House confirmation statement — what it is, when it's due, what information you need, and the difference from annual accounts.
Dormant Company Accounts & CT600: Filing Guide for Companies That Aren't Trading
How to file dormant company accounts with Companies House and a nil CT600 with HMRC. Step-by-step guide with deadlines and requirements.
HMRC Penalties for Corporation Tax: Late Filing, Late Payment & Errors
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.
Construction Industry Scheme (CIS) & Corporation Tax: CT600 Guide
How CIS deductions work for limited companies, how to reclaim CIS through payroll and HMRC's repayment service, and how Corporation Tax is calculated on construction profits.
Trading Losses & Corporation Tax: How to Claim Relief on Your CT600
Complete guide to claiming trading loss relief on your CT600 — carry back, carry forward, group relief, and terminal loss relief explained with examples.