In 2017 this rare banknote was sold at 1, 68,800 pounds. This note was in circulation from 1971 to 1988. The features that make this note rare are; it consists the signature of the Chief Cashier of the Bank of England.
Another factor that made this note valuable is the serial number, as the note is printed in sheets with an assigned serial number to each of them. The serial number is made up of a two letter prefix.
The prefixes starts from AA and a batch number which starts from 01. According to Warwick & Warwick Auction house, any of this noted series with AA01 batch is potential a rare specimen which the particularly because number 000001 is always presented to the Queen and 000002 is always presented to Prince Philip.
Image Courtesy: penny.co.uk