No, the paper Bank of England notes £5, £10, £20, £50 aro no longer a legal tender.
Paper £5 and £10 stopped being a legal tender in 2017 and 2018. Bank notes £20 and £50 were a legal tender until 30th September 2022.
Paper money notes are not accepted in shops as a legal tender, so you can't pay with them. After 30th September 2022, you have to use the new polymer bank notes.
But you can exchange paper money in the Bank of England.