The closure will run from 10pm on Friday 3 November until 7am on Monday 6 November, with no access to employee expenses, marriage allowance and tax credits service over the weekend.

If a taxpayer tries to access these services during the migration, they will be ‘provided with suitable messaging advising them the service is currently unavailable’.

The IT work will focus on the migration of existing legacy IT systems to cloud based hosting, which is integral to HMRC’s push to move to improve its web services as part of an online first approach to taxpayers with a sharp reduction in the amount of call centre support. The plan is to cut telephone support by 30% by the end of 2024.

On the closure, HMRC said: ‘We will be making planned upgrades to some of our IT, moving more of our internal systems to cloud-hosting.

‘This will help to make them more resilient, reliable, and secure.

‘The work involved means that some of our webchat and digital services will be either fully unavailable or have limited functionality during migration.

‘We have planned for this migration to take place over a weekend to minimise disruption on our customers.’

There will also be limited helpline support over the weekend. Depending on the query, HMRC said that webchat advisors for some lines would only be able to provide general advice for individuals calling helplines about self assessment issues, online services or any caller who needs extra support.