Her Majesty’s Revenue and Customs (HMRC) has been experiencing difficulties with a new online tool that it launched today after over 400,000 people tried to access it.

The tool allows UK residents to calculate how much they are being taxed and how the government is spending it.

A spokesperson for HMRC told Computerworld UK that due to the “weight and volume of traffic” people were unable to access the site.

“It’s something we haven’t done before and it is difficult to gauge how popular these things will be. Four hundred thousand people is a lot of people,” said the spokesperson.

“We are very sorry about this and we are trying to get it back on track again, but it will take some time.”

HMRC couldn’t give any firm indication of when the service will be available again, but did say it would try to have it up and running later this afternoon. HMRC’s Twitter account posted a message saying that the tool was “now being restored”, but at time of publication seemed to still be experiencing problems.

To accompany the online tool, HMRC has also launched a mobile app with the same capabilities that is available for download on iOS and Android. The mobile site hasn’t experienced any difficulties.