The Bank of England has withdrawn the £50 notes that feature Sir John Houblon on the reverse of the note. These are withdrawn from circulation from the 30th April 2014. These notes are sometimes referred to as the £50 E series note.
The Sir John Houblon £50 notes have been in circulation since 1994, and since that time there have been many new advances in bank note design and security features.
The new-style £50 note which features Matthew Boulton and James Watt has been in circulation since November 2011.
After the 30th April 2014 most banks and building societies will still accept the Sir John Houblon £50 notes for several months for deposit into customer accounts. Agreeing to exchange notes is at the discretion of the individual institution. Barclays, RBS, NatWest, Ulster Bank and the Post Office have all agreed to exchange the Sir John Houblon £50 notes for both customers and non-customers up to the value of £200 until the 30th October 2014.
The Bank of England will always exchange its older series notes. The process is to present the notes in person or to a send by post (at the senders risk) to: Dept. NEX, Bank of England, Threadneedle Street, London EC2R 8AH.