A boy who dressed as a character from Fifty Shades of Grey was excluded from his school's World Book Day celebrations, according to his mother.
Liam Scholes, 11, went to Sale High School as Christian Grey from the explicit novel, wearing a grey suit and carrying cable ties and an eye mask.
His mother Nicola Scholes, a teacher, said the Greater Manchester school excluded her son from photographs.
The school said he was able to join in after "his costume was modified".
Lynn Nicholls, headteacher at the school, said: "The decision reflects the school's high standards in terms of student behaviour, welfare and safeguarding.
"The aim of our world book day events was to celebrate and encourage reading and we are disappointed that what was a fantastic day for our students has been marred by this issue."
Ms Scholes said she feels Liam's outfit was actually more appropriate than some of the costumes worn by others.
She said it was deemed "appropriate for a teacher to dress up as a serial killer" and "acceptable for kids to dress up as people that kill others" and "come in with [toy] guns".
"Liam was advised to dress as James Bond... but [he] was a promiscuous character who kills people," she said.
"Personally, I'm more offended by a murderer."
Ms Scholes told BBC Radio 5 Live that her son's classmates all found it funny, but that the school had no sense of humour.
"It has been massively blown out of proportion. It was meant as a laugh and tongue-in-cheek."
She said she would not have allowed her eight-year-old son to dress up as the character because he was still in primary school.
However, she said secondary school children "all talk about sex" and Liam's school friends all knew who he had dressed up as.
"For the past month [Fifty Shades of Grey] is all that you've seen on TV."
The Fifty Shades of Grey trilogy is described by author EL James as a "provocative romance".
The film version, which was released in the UK last month, contains "strong sex and nudity" and has been given an 18 certificate by the British Board of Film Classification.
It stars Jamie Dornan as Christian Grey and Dakota Johnson as his lover Anastasia Steele.