The story behind Father Christmas coming down the chimney on Christmas Eve is an interesting one. Our friends at the Guild of Master Sweeps have detailed it here, read all about Santa Claus / Sinterklaas / St Nic or just good old Father Christmas and how he came to bring presents to children down the chimney:
https://findachimneysweep.co.uk/chimneys-folklore-at-christmas/
Ho ho ho!
