A mum took to Facebook to beg for help with her autistic son's obsession with the London Underground - and the kind response "blew her away".

Laura Flora made the plea after her 23-year-old became fascinated with how many platforms there are at every Tube station in the captial.

And users of the social network stepped up the the plate - with more than 500 helpful comments appearing in just over three hours.

Laura posted: "I need your help!

"I have a 23-year-old autistic son who is OBSESSED with trains.

"All trains in rotation but currently his obsession is the Underground and how many platforms there are at each station.

"And I mean EACH station. I would REALLY like to not have to spend the next three 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 said she was aware it was a tall order, but really wanted to create a big poster with the info for her son.

"I just have a real want to not have to ride the Tube with a notebook and an autistic man," she added.

She then received an overwhelming response from Facebook users, detailing platforms, stations, and even extra tidbits about disused lines.

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

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

"I am working my way through everyone's posts and, if I miss a like, its still there I promise."

She added: "I would like to add all your names to a list so when he looks and sees it he knows that all these wonderful, WONDERFUL people helped him."

Laura said she would start putting the poster together hopefully to surprise her son when he came back from visiting his dad.

She said: "My son cannot travel alone and has to have 24/7 care so I think him just knowing how to get to places is his way of dealing with the lack of independence he has in real life.

"He likes to tell me how to get to places, it makes him feel useful."

"Thank you for helping him."