John "Abs" Denham is a fictional character from the BBC medical drama Casualty, played by actor James Redmond. He first appeared in the series eighteen episode "Flash in the Pan", broadcast on 4 October 2003. Abs was introduced at a time producer Mervyn Watson had revamped the show's cast. Redmond was offered the role of Abs which he was happy to accept because he was "fascinated" with the psychology of the character. Abs is characterised as being a "charming but eccentric loner". He is also portrayed as very "gullible", which writers took advantage of during his first relationship stories. They paired him with paramedic Nina Farr, but soon added her scheming step-sister Ellen Zitek into the story. Ellen realises that Abs is gullible and concocts lies to convince him to marry her so that she can obtain a visa to remain in the UK. He risked prison when he realised the marriage was a sham and ended it.

James William Forbes Redmond is an English actor, presenter, stand-up comedian and model, known for his roles as Abs Denham in Casualty and Rory Finnigan in Hollyoaks.