The real reason for the new £10 note...

It's so people are eventually forced to pay any cash savings they have into the bank. The bank informs HM Revenue and the DWP of any large cash deposits, they in turn then investigate the saver for having possible undeclared earnings or undeclared savings. It doesn't have to be a huge amount, just enough to tip someone over the earnings or savings limit.

A timely reminder that you have less than a week to dispose of any old £10 notes.

If paying them into a bank or building society I suggest paying in odd amounts so as to avoid being asked any awkward questions by HM Revenue or the DWP, eg: £490 rather than £500.

Final reminder, today is the last day you can spend any of the old ten-pound notes. From tomorrow they cease to be 'legal tender' which means you cannot force someone to accept them as payment although somes shop may still accept them for a short period.