I found my bedroom light bulb had failed yesterday - it's a standard bayonet
fitting below a ceiling rose. However, it wasn't as simple as just changing
the lightbulb - the bulb had fallen out of the fitting. Inspection of the
socket showed that it had largely melted, in fact one of the two metal
spring-loaded electrical connection pins had dropped out, covered with burnt
plastic and melted lead from the bulb contact. The bulb had fallen out
because one of the socket cut-outs, which retain the lugs on the bulb, had
just disintegrated or melted with the heat.

It sounds like I was lucky not to have a house fire, wasn't I (or not?)?
Why would this happen? Why didn't the relevant MCB on my CU trip (they seem
to do so - irritatingly - every time a bulb in the house blows!) The fitting
was only about 4 years old, is wired perfectly OK, and it's months since
I''ve changed the lightbulb which has worked perfectly ever since. I find
it pretty scary to think what migh have happened, and I haven't a clue why.

Thanks
Dave