Bank of England G M Gill £20 note from 1988. 

Country/Issuer: UK/Bank of England
Denomination: £20 Twenty Pounds
Chief Cashier/Signature: G M Gill
Year: 1988
Serial Number: 35W 591274
Grade: VF+. One heavy crease, folds and general handling with a little dirt. One pinhole at the top of the watermark.
Duggleby: B355
 
All gradings are my own opinion and I would ask that you study the images carefully to make your own assessments.