Dispelling the myth that Londoners are all miserable and self-absorbed, hundreds of people have helped a mother to count the number of platforms across the London Underground network for her train-obsessed son who has autism.

Laura Flora told the "Sh** London" Facebook group - normally used for sharing photos of the capital’s less glamorous moments - that her 23-year-old son is passionate about trains, but needs round-the-clock care and therefore cannot travel alone.

His latest fixation is finding out how many platforms there are at all 270 stations that make up the network, she said.

“I would REALLY like to not have to spend the next 3 months of my life getting on and off trains counting platforms, so how about if you are at a tube station you could count the platforms if you can see them and tell me which line you are on and North/South/East or Westbound," she wrote on the group page.

Flora told members that she planned to create a wall poster to collate their contributions, but would be equally happy if someone from Transport for London came forward with the information.

In less than a day, 700 people had responded to Flora’s request.

Overwhelmed by the reaction, Flora edited her original post to thank the “awesome” group members, some of whom had offered additional information.

“Oh my GOD!! How awesome is everyone!!! I am absolutely blown away by this post, seriously!" she said.

“Extra thanks for all the extra little bits of information! The end of the lines, the unused platforms. All this little detail really matters to him," she added.

London's abandoned Underground stations Show all 6 1 /6 London's abandoned Underground stations London's abandoned Underground stations South Kentish Town South Kentish Town was opened in 1907 by the Charing Cross, Euston & Hampstead Railway and remained for just 17 years until it was closed in 1924 due to low passenger usage London's abandoned Underground stations Mark Lane Mark Lane is a disused station, once served by the Circle and District lines. It takes its name from Mark Lane, the street on which it is located, west of the current Tower Hill station that replaced it in 1967 London's abandoned Underground stations Embankment sub-station The sub-station at Embankment was opened on 30 May 1870 by the District line when the railway extended its line from Westminster to Blackfriars London's abandoned Underground stations Down Street Down Street is a disused station on the London Underground, located in Mayfair. It operated from 1907 until its closure in 1932 London's abandoned Underground stations British Museum British Museum was opened by the Central London Railway in 1900. In 1933, with the expansion of Holborn station, less than 100 yards away, British Museum station was permanently closed London's abandoned Underground stations Aldwych Aldwych was opened in 1907 with the name Strand. Suffering from low passenger numbers, a weekday peak hours-only service survived until closure in 1994 AFP/Getty

Flora also hit back at the suggestions that she could have lied to her son rather than attempting to put together an accurate map.

“I know to some it seems easier to lie, but I don't lie to him, I would rather do the miles than deceive," she responded.

The mother explained thats she planned to surprise her son with the map, and asked those involved to send her their names “so when he looks and sees it he knows that all these wonderful WONDERFUL people helped him.”

Around one in 100 people have autism spectrum disorder in the UK, according to the NHS.

Developing a highly specific interest in a subject is among the symptoms of autism.