It's just a theory, but I reckon when things like this happen, Southern are only too happy to cancel the trains that stop at FH etc. "Oh, they've got the Overground, they won't mind." Except they forget how tiny the Overground trains are compared to those lovely 10-carriage Southern beauties.

Which is how come I watched lots and lots of Southern trains go by this morning on the "fast" line, i.e. trains were still running - kinda, whilst not being able to actually get on an Overground train at all due to their massive overcrowding.

Disclaimer: some I couldn't actually physically get on. Others I had no desire to try, what with being 4'11" and quite enjoying oxygen.

In the end I got the Overground to Crystal Palace, and stayed on as it set off back the other way - result, and definitely my future tactic!