The polymer £5 featuring Sir Winston Churchill on the reverse, introduced in September 2016, will be the only legal tender £5 note after this date. The paper £5 note, which features a portrait of Elizabeth Fry on the reverse can be used until 5 May 2017 and from there on this note will be a counterfeit note. The affected notes cane be exchanged at the Bank of England in person or by post.  For more details visit http://www.bankofengland.co.uk/banknotes/Pages/withdrawn/default.aspx