HM Revenues and Customs has been criticised for taking IT systems offline for routine maintenance just days before the end of the tax year.

Last week, the tax collector warned businesses that a range of systems will be offline from today until Wednesday 11 April, including systems that allow businesses to pay tax. The deadline for outstanding PAYE or National Insurance payments is April 21.

Phil Orford, the chief executive of the Forum of Private Business, said it was the wrong time to schedule the work. "Many firms will find it hard to understand why HMRC has chosen to do a major upgrade to its IT systems at such an important time of the year in the tax calendar."

Orford said he hoped that any mistakes caused by the shutdown would be dealt with quickly by HMRC, but warned that reimbursement can take "months and months of wrangling to sort out" HMRC’s mistakes, based on its members’ experiences.

"The fact that [the shutdown] was only announced last week as well shows little understanding for the needs of businesses," he said.

An HMRC spokesperson told Information Age that shutting down key systems for maintenance and upgrades is an annual event. "It’s literally something we do very year," she said. "These key deliveries are known as Enterprise Releases, and the amount of change they deliver is increasing every year.

"Changes for the new tax year are made in April, and projects that are not related to the tax year are generally delivered in October."