How a fake Tube sign became a symbol for London's response to terror

The London Underground's message boards are sharing some much needed inspirational messages of support across the city today.

But some are fakes, like this one:

However, it was so good (or possibly convincing) that Tory MP Simon Hoare fell for it when he brought it up in the House of Commons this morning:

Would my right honourable friend agree with these words, written by a worker on the London Underground yesterday afternoon, penned on a public notice board shortly after the events. My judgement is that he or she speaks for the whole country irrespective of faith or creed.

Theresa May replied:

I think that is a wonderful tribute and in a very simple way has encapsulated everything everyone has said in the house today.

And, like any massively shared image on the internet, it's become a meme:

And here's the original, if you were curious what it said: