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#  UK VAT check plugin

Details    Written by: Administrator    Category: [Pther extensions](/support/documentation/hikashop/other-extensions)     Published: 10 November 2026     Hits: 4

## Installation

1. The plugin checks VAT numbers that start with GB against the "Check a UK VAT number" service of HMRC, the British tax office. You need a client ID and a client secret for it: they come from an application of your own registered on the HMRC Developer Hub and subscribed to that service.
2. Install the plugin with the HikaShop or Joomla installer, then publish it in the plugin manager (Hikashop - UK VAT check).
3. Open the settings of the plugin, type the client ID and the client secret, and save. Keep the environment on "Sandbox" while you test with HMRC's test numbers, then set it to "Production".
4. In the configuration of HikaShop, set "VAT number check" to the online check, so that VAT numbers are checked while customers enter their address.

The plugin needs the PHP cURL extension. The VAT numbers of the European Union are still checked by HikaShop itself. Without a client ID and a client secret, GB numbers are left unchecked.

## Configuration

![The UK VAT check settings](/images/doc/plugins/ukvat/plg_hikashop_ukvat_settings.png)

- **Environment**: Sandbox while you test your credentials with the test VAT numbers published by HMRC, Production on your live shop. Production by default.
- **Client ID**: the client ID of your application on the HMRC Developer Hub. Left empty, GB numbers are not checked.
- **Client secret**: one of the client secrets of that application. Keep it private. Left empty, GB numbers are not checked.
- **Your VAT number**: optional, the 9 or 12 digit VAT number of your own business. When it is filled in, HMRC gives a consultation number for each check, which is your proof that you verified the number, and it is written in the HikaShop log file.
- **When the check cannot be made**: what to do when HMRC cannot be reached or answers with an error that says nothing about the number, for instance wrong credentials or a service that is down. "Accept the number" (default) lets the customer go on, "Refuse the number" blocks them until the check works.
- **Timeout**: the number of seconds to wait for HMRC before giving up, 10 by default. The customer waits during that time, so keep it short.
- **Debug mode**: No by default. Yes writes every call and answer in the HikaShop log file. Turn it off once everything works.

## Troubleshooting

- **"This VAT number is not registered in the United Kingdom. Please check it and try again."**: HMRC knows no business under that number. The customer has to correct it.
- **"The VAT number you entered is not valid"**: HMRC read the number as malformed.
- **"Your VAT number could not be verified at the moment. Please try again later."**: shown with "Refuse the number" when the check could not be made. Look at the HikaShop log file (turn on Debug mode): the line tells whether the credentials were refused, the service did not answer, or HMRC returned an error.
- **GB numbers are accepted without any check**: the client ID or client secret is empty (the log says so), or the number is not a normal 9 or 12 digit number (the numbers of government departments and health authorities are not checked), or HikaShop is not set to check VAT numbers online.