Not sure if anybody else has tried to take a look at the new HMRC Tax App, but just tried myself and it appears to be broken or down already.
I thought it was a good idea, as the layman does struggle to understand exactly how much tax her or she pays. I've got many educated clients who have no idea how much tax or the rate of tax that they pay. They mainly trust me to advise them how much they should pay and when.
Hopefully the initial problems will be resolved soon and we can all take a look and see how useful the app may or may not be.