Due to the huge increase in phone calls and emails regarding the underpayments I have written up my advice on how to handle your case here: PAYE Fiasco update and Summary of how to fight your case http://www.cheapaccounting.co.uk/blog/?p=1436 Please follow the advice given in the first instance. The advice also includes help on the demands for immediate payment that have been sent out in the last couple of weeks. Note... · Send all correspondence registered post · Do not bother to phone them - if you can get through they will just advise you to pay up · It is taking HMRC weeks / months to respond to letters Although this doesn't help, as you will know this is a common situation - over 1 million people are in the same situation as you. The Daily Mail has been running regular updates on this matter - so please read there for significant future developments. The only way to make this situation better is if someone in Government instructs HMRC to adopt a common sense approach to handling the 1 million cases that they have outstanding. Sending out demands for payment of the underpaid tax in March has only worsened the back log situation. The back log is unlikely to ease soon unless some significant action is taken by HMRC. Maybe a miracle could happen.