Image copyright Eric Tolentino

Jessica Anderson ran the London Marathon trying to beat the world record for the fastest marathon time for a woman wearing a nurse's uniform.

Jess, who is a nurse herself, beat the current record - of three hours, eight minutes and 54 seconds - by 22 seconds.

This wasn't enough to make her a record breaker though.

That's because she did it wearing medical scrubs - and Guinness World Records said this does not meet its criteria for a nurse's uniform.

'Carry On nurse'

When Jess, a senior sister at the Royal London Hospital, was training for the marathon she realised that the record time for the fastest nurse to run a marathon was very close to her personal best.

She told Guinness World Records that she wanted to challenge the record and sent in photos of her in the uniform, so officials could track her during the race.

But she was told she would not be eligible for a record if she ran in her scrubs because they did not "meet the criteria".

An official explained to her: "For the purposes of this record, the nurse's uniform must include: a blue or white nurse dress, a white pinafore apron, a traditional white nurse's cap. Tights are optional."

Or as Jess sees it, "an old-fashioned, Carry On version of a nurse".

She says these costume rules would apply to men or women wanting to run in a nurse's uniform for a record bid.

Image copyright Getty Images Image caption Acceptable running attire?

Jess wrote back asking them to reconsider what she calls this "outdated and frankly quite sexist" attitude for future races.

She pointed out that almost all the nurses on her ward wear scrubs.

A representative for Guinness World Records explained to Jess that this is too similar to their requirements for a doctor's uniform: scrubs, white coat and stethoscope.

In messages seen by Newsbeat, a spokesman told her: "In order to maintain a different level of challenge the 'nurse' costume has to be different, hence the requirement for the old fashioned, stereotypical attire."

He also told Jess that other professions do not have realistic uniform criteria, as "the fastest marathon dressed as a chef requires a chef's hat to be worn and a large pot to be carried".

While Jess knows this might not seem like the biggest problem in the world, but she thinks it "really has an impact on the public perception of nursing".

She says it's a modern profession that is open to both men and women, so the idea that nurses have to wear a dress and pinafore is "baffling".

Newsbeat has asked Guinness World Records for a comment, but it has not got back to us.

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