Contacting HMRC
How to contact HMRC, including the dedicated agent helplines available, the online services helpdesk, HMRC's agent webchat, 'Where's my reply?' tool and how to update your contact details.
HMRC has paused Agent Reference Number (ARN) checks until 17 November 2026.
Since 18 August, HMRC has been asking some tax advisers to provide their ARN when contacting HMRC by telephone or webchat. This is to check whether they have registered for an Agent Services Account (ASA) as part of the Modernising and Mandating Tax Adviser Registration rollout.
HMRC has now paused ARN checks for this purpose until 17 November 2026 to allow tax advisers additional time to prepare for these changes. Tax advisers may still be asked for their ARN in other situations, such as when HMRC is investigating an issue on their behalf. Existing security, identity and client-authorisation checks will continue during this period.
ARN checks will resume from 18 November 2026 for businesses that are required to register with HMRC as tax advisers.
All relevant employees who interact with HMRC should make sure they have their business’s ARN ready to share from this date. The ARN is an 11-character reference made up of four letters, including ‘ARN’ followed by seven digits, for example: XARN1234567.
HMRC’s agent webchat is an agent-only channel providing a faster alternative to telephony for many Self Assessment and PAYE queries. You can speak to an adviser online about some of your most common queries.
This service is available Monday to Friday from 8am to 6pm.
Queries best suited to agent webchat
HMRC recommends agents use webchat for the following query types:
- PAYE queries
- registrations
- deregistrations
- progress chasing (excluding Self Assessment repayments, appeals and returns)
- reactivations
- Making Tax Digital
A callback will be made by an HMRC adviser if your query cannot be resolved through webchat.
We will continue to accept chats on other topics unless they fall into the ‘not suitable’ list below.
Queries not suitable to agent webchat
These queries are not suitable to agent webchat and should be resolved by phone:
- statements and payment allocations including:
- clarification on remissions
- over-repayment cases
- multiple payments
- allocation or reallocations with required analysis
- progress chasing a return, Self Assessment repayment or an appeal — where the date in the ‘Where’s My Reply?’ tool has passed
- amending a return online
- class 4 miscalculations
- complex or technical queries requiring specialist teams including:
- Capital Gains Tax
- double taxation
- basis period reform
- chargeable events
- non‑residency
HMRC has dedicated helplines and contacts for tax agents.
If you need contact details for a tax and duty that does not have an agent dedicated telephone number or address, you can search the list of HMRC contacts.
Find out when you can expect to get a reply from HMRC to a query or request you have made.
You can use this tool for queries or requests you’ve made about:
- Child Benefit
- Construction Industry Scheme (CIS)
- Corporation Tax
- employers’ PAYE
- Income Tax
- National Insurance
- Self Assessment
- tax credits
- VAT
As an agent, you can also check how long it will take HMRC to:
- register you as an agent to use HMRC online services
- process an application for authority to act on behalf of a client
- amend your agent details
Helplines frequently used by agents on behalf of their clients.
Bereavement helpline
Contact the bereavement helpline for help with tax after someone dies if you’re dealing with their:
- Income Tax and Capital Gains Tax before they died
- estate in the administration period, without sending a tax return
Deceased Estate helpline
Contact the deceased estate helpline to get specialist advice on a deceased person’s estate, if you need to register for and send a tax return for the administration period.
Contact HMRC with technical problems when using HMRC online systems, sending forms online, error messages and using HMRC free software and tools.
Find out what to do if your tax agent business is changing in some way, including if:
- your business is changing legal entity
- your agency firm is merging with another one
- you want to move clients between client lists
- your agency is de-merging from another one
- you stop trading as an agent
Tell HMRC about changes to your contact details and anti-money laundering supervision details as a tax agent.
You can view or update the following contact details with HMRC:
- business name
- business address — this cannot be a PO box address
- phone number