A customer of Ryanair was left astounded after receiving a security code featuring an expletive that is 'as vulgar as a word can get.'

Joseph, who hails from Chessington, Kingston-Upon-Thames, registered an account on Ryanair's website last Sunday (March 19) to purchase tickets for his relatives to visit Stansted Airport.

However, the 43-year-old was taken aback when he received a confirmation email that was "clearly unacceptable".

The email greeted the project manager and prompted them to verify their myRyanair account using an eight-digit security code: d9c*ntg5.

The sender clarified that the symbol represented by * was actually the letter 'u'. Joseph was surprised and admitted that he would have thought it was a scam if he hadn't recently created the account himself.

"In my line of work we have to have filters to ensure that we're covered in things like that," he said.

"I was shocked that a company of that size doesn't have [the correct] measures in place. I think it's clearly unacceptable and about as offensive as a word can be.

"If I hadn't been doing it [signing up for the website], I would have assumed it was a hoax. I was really shocked and just surprised that I could receive such a thing."

"You don't know what sort of words can go out to other people, and other people may be more easily offended by words of that nature," he reflected.

"If people have kids as well. You don't want it to be going to underage people. If I had a son and he was signing up, I wouldn't want him to be privy to those sorts of words."

"I know there's no malice from Ryanair's side - it's just a really poor oversight in their IT vetting."

"They should strengthen their IT systems to prevent anything like this from happening in the future."

Joseph plans to avoid using the airline regardless of whether or not any action is taken.

"I've shown the email to a couple of friends. Their reactions were a mixture of comedy and utter disbelief," he said.

"I haven't had the best customer experience from Ryanair, period. I try to avoid them where possible.

"I guess after this, it certainly wouldn't draw me to using them anymore than I have been in the past."

Despite Joseph's argument that the "offensive" security code could have been easily avoided, Ryanair did not take responsibility or offer an apology to him. A representative of the airline stated:

"This customer did not receive 'an inappropriate word via email as his security code'; this is a standard security code mechanism in which customers receive a randomized sequence of letters and numbers generated using a third party to verify access to their accounts."