A gay man who took his partner’s car to a car wash in Oxford was furious to discover that the attendant had scrawled homophobic graffiti on the roof.

Robert Greenberg, 21, was with his partner Jack Taylor and friend Grace Elliot when they took Mr Taylor’s blue Renault Clio to the Arc Car Wash in Cowley.

He told the Oxford Mail the attendant had used a ‘washable’ marker to write £5 on the roof to let a colleague know which wash they had paid for, which is normal practice.

However, he then discovered that the man had written ‘gay’ on the roof with an arrow pointing to the passenger seat, where he had been sitting.

Mr Greenberg, a student, said he laughed the “offensive” graffiti off at first but later realised he had not been meant to see the writing.

He said: “I’m sure this particular member of staff believed this to be washable and for neither myself nor my partner to read it. Grace and Jack told me to laugh it off because it was meant to be a joke, but I thought it was a bit more serious than a joke.

“When I got home I spoke to my other housemates about it and I realised he never intended me to see it, it was a joke between them, and I found that quite offensive.”

He said he was offered 12 free car washes after complaining to the company and that the writing was still visible a week later.

Site owners Anduff Car Wash Limited told the newspaper that the attendant was a self-employed commission agent who had been sacked.

The company added it had apologised to Mr Greenberg.

Stonewall chief executive Ben Summerskill said the incident was “regrettable” and the company was likely to lose customers.