I find the idea that an appliance could "blow up" on a UK power supply if you reverse the "live" (phase) & neutral in the plug top a little over dramatic!
During the course of my work I have encountered plugs with reverse polarity on many occasions, & all the appliances work normally. This does not mean to say they are safe, as any single pole control devices; switches, thermostats etc. would be in the neutral conductor. This could be a shock hazard, if for example you were changing a bulb & accidentally touched the pins, thinking it was safe with the switch off.
British regs. prohibit a single pole switch in the neutral, if the neutral is switched all associated phases must be switched simultaneously.
The purpose of the fuse in a 13A BS1363 plug is to protect the appliance cord only from short circuit. If the appliance requires additional protection it has to built in to the appliance, I believe this is an IEC standard.
Reverse polarity in the actual fixed installation wiring could be very dangerous, depending where it occurs.
The worst case would be TNC-S (PME) reversed
on the incoming supply before the cut-out (I know of this happening). All bonded metalwork would be live at 240V, along with every earthed point & appliance in the installation.
This is the 1 downside to TNC-S earthing system.
These are just a couple of reasons that us Brits are obsessed with maintaining polarity throughout our "eccentric" electrical installations.
As other members have stated the neutral is always permanently & solidly earthed in UK public supply systems.
Most systems are TNC-S or TN-S, with TT systems only used for rural supplies (though TNC-S is the norm in my area), building sites & petrol service stations (TNC-S not permitted) or any other location where PME (TNC-S) system is not allowed.
