Every UK limited company must deal with HM Revenue and Customs (HMRC) at some point over corporation tax, whether it’s a payment query, a filing deadline, or a dispute over a tax code. Knowing exactly how to reach HMRC saves time and avoids costly penalties.
This guide covers every contact channel available: phone, online, post and agent support so you can get the right answer fast.
What Is Corporation Tax and Who Needs to Contact HMRC?
Corporation tax is a tax on the taxable profits of limited companies foreign companies with a UK branch and some clubs or associations registered in the UK. If your company is trading you’re legally required to register with HMRC, file a Company Tax Return (CT600) and pay any tax owed within nine months and one day after your accounting period ends.
Directors company accountants and appointed tax agents may all need to contact HMRC for reasons such as:
- Registering a new company for corporation tax
- Checking payment deadlines or outstanding balances
- Querying a penalty or late filing notice
- Reporting changes to company details
- Requesting a refund or correcting an error on a return
HMRC handles millions of corporation tax queries each year and having the correct contact route ready before you call or write saves significant back and forth.
HMRC Corporation Tax Helpline Number
The quickest way to resolve most queries is by phone. HMRC’s dedicated Corporation Tax helpline connects you directly with an advisor trained on company tax matters.
| Contact Method | Details |
| Phone (UK) | 0300 200 3410 |
| Phone (outside UK) | +44 151 268 0571 |
| Opening Hours | Monday to Friday 8 am to 6 pm (closed weekends and bank holidays) |
Before calling, have your ten-digit Unique Taxpayer Reference (UTR) company registration number and Government Gateway details ready. HMRC advisors will ask security questions to verify your identity before discussing any account information.
Contacting HMRC Online Through Your Business Tax Account
Most routine corporation tax tasks can be handled digitally without ever needing to call. HMRC’s online services are available around the clock and reduce the risk of postal delays.
Through your Business Tax Account registered on the Government Gateway, you can:
- View your corporation tax position and payment history
- File your Company Tax Return (CT600)
- Check upcoming deadlines and penalty notices
- Update company or contact details
- Send secure messages to HMRC through your account inbox
If you haven’t registered yet, you’ll need your company’s UTR, which HMRC posts automatically within a few weeks of company incorporation. Setting up online access early avoids delays when a deadline is approaching.
Using Webchat and the HMRC App
For quick questions that don’t require detailed account access, HMRC’s webchat service connects you with a live advisor through the website. It’s available on select pages within the corporation tax section and is often faster than phone queues during busy periods.
The HMRC app available for iOS and Android also allows limited account monitoring, including viewing tax codes and making certain payments, though full corporation tax management still requires the desktop Business Tax Account.
Webchat is best suited for:
- General guidance on filing requirements
- Clarifying which form or return applies to your situation
- Basic navigation help for online services
For anything involving specific figures or disputes on your account, phone or written correspondence remains more reliable.
Writing to HMRC by Post for Corporation Tax Matters
Some situations still require written correspondence, particularly formal appeals, complex disputes or when submitting documents that can’t be uploaded online.
HMRC Corporation Tax Postal Address:
HM Revenue and Customs
Corporation Tax Services
BX9 1AX
United Kingdom
When writing to HMRC, always include:
- Your company’s UTR
- Company registration number
- A clear subject line describing the query
- Copies (not originals) of any supporting documents
Postal replies typically take several weeks, so this channel suits non-urgent matters rather than time-sensitive deadlines. For anything approaching a filing or payment date, phone or online contact is faster and safer.
How to Contact HMRC Through an Accountant or Tax Agent
Many companies appoint an accountant or tax agent to manage corporation tax on their behalf. Agents use the Agent Services Account, a separate HMRC portal to file returns, check client balances and communicate directly with HMRC’s Agent Dedicated Line.
Benefits of using an agent to contact HMRC include:
- Faster resolution through the dedicated agent phone line
- Fewer identity verification delays since the agent is pre-authorized
- Reduced risk of missed deadlines through professional oversight
To authorize an agent, you’ll need to approve their request through your Business Tax Account or complete HMRC’s form 64-8. Once authorized, the agent can speak to HMRC on your company’s behalf for most corporation tax matters.
What to Do If You Disagree With an HMRC Decision
If HMRC issues a penalty assessment or decision you believe is incorrect, you have the right to challenge it. The process generally follows these steps:
- Request a review: Write to HMRC within 30 days of the decision explaining why you disagree.
- Provide evidence: Attach any records, correspondence or calculations supporting your position.
- Await the outcome: HMRC will confirm, amend or cancel the decision after reviewing your case.
- Appeal to a tribunal: If unresolved, you can escalate the matter to the independent Tax Tribunal.
Keeping detailed records of all communication, including dates, reference numbers and advisor names strengthens your case if a dispute escalates.
Tips for a Faster Response When Contacting HMRC
A few practical habits make dealing with HMRC noticeably smoother:
- Always quote your ten-digit UTR and company registration number
- Call during off-peak hours early morning tends to have shorter queues
- Use online services for routine tasks rather than tying up phone lines
- Keep a written record of every call, including the date, time and advisor’s name
- Set calendar reminders for filing and payment deadlines to avoid last-minute contact
Following these steps reduces wait times and helps you get accurate answers on the first attempt.
Final Thoughts
Contacting HMRC for corporation tax inquiries doesn’t need to be complicated once you know which channel fits your situation. Use the phone helpline for account-specific and urgent questions, the Business Tax Account for routine filing and payment tasks, webchat for quick guidance, and post only when written correspondence is genuinely required. Companies working with an accountant or tax agent often find the Agent Dedicated Line resolves matters even faster. Whichever route you choose, having your UTR company registration number and clear details of your query ready will make every interaction with HMRC quicker and more productive.
FAQs
What Is The Phone Number For HMRC Corporation Tax Inquiries?
The main number is 0300 200 3410, available Monday to Friday from 8 am to 6 pm.
Can I Contact HMRC About Corporation Tax Outside The UK?
Yes, use +44 151 268 0571 if calling from outside the United Kingdom.
How Do I Check My Corporation Tax Balance Online?
Log into your Business Tax Account using your Government Gateway details to view your balance payment history and filing status.
What Information Do I Need Before Calling HMRC?
Have your company’s ten-digit UTR company registration number and Government Gateway login ready for identity verification.
Does HMRC Offer A Webchat Service For Corporation Tax?
Yes, webchat is available on select HMRC website pages and suits general or quick queries.
What Is The Postal Address For HMRC Corporation Tax Correspondence?
Write to HM Revenue and Customs Corporation Tax Services, BX9 1AX, United Kingdom.
Can My Accountant Contact HMRC On My Behalf?
Yes, once authorized through form 64-8 or your Business Tax Account, an agent can use the Agent Dedicated Line to handle queries directly.
How Long Does HMRC Take To Reply To Written Correspondence?
Postal replies typically take several weeks, so post suits non-urgent matters rather than deadline-sensitive issues.
What Should I Do If I Disagree With An HMRC Corporation Tax Decision?
Request a formal review within 30 days to provide supporting evidence and escalate to the Tax Tribunal if the matter remains unresolved.
What Is The Best Time To Call HMRC To Avoid Long Wait Times?
Early morning, shortly after lines open at 8 am, or later in the afternoon tends to have shorter queues than the midday period.
