Engine cut out while driving, no warning, green key light flashing.
 

So I had a strange cut out of the engine which I’ve never had before. I pulled off the dual carriage way off down a slip road, put the clutch down, changed down a gear and tried to give it a few revs but heard nothing, looked down at the dash and it was blank, no revs or speed, basically just off. The engine had just cut out, the only think on the dash was a green key symbol flashing. Slightly disconcerting having the engine cut off as I was worried the steering would lock but I was going in a straight line so didn’t happen. I pressed the starter button thinking the engine may have stalled but nothing, when I came to a stop I pulled the keys out, back in and restarted with no problem and carried on my way.

I’m assuming this is some kind of problem with the immobiliser? I’ve seen a few posts saying this but when people have had this immobiliser problems it seems to be when they are starting up, not whilst driving!

If this happens again is there a risk the steering could lock?

The car has been in use, battery seems fine. The only thing out of the ordinary was I had some new pads fitted and gave the garage my spare key (which never gets used) and I went back to using my normal key the next day, don’t know if this could have done some funny business with the immobiliser if the spare key is faulty.
I’ve had the spluttering at low revs and stalling problem last year but this was different, just cut off, had been 100% fine before this. The car is standard, mods on engine, transmission etc.

Thanks in advance for any advice!

It sounds like a short in your key cylinder. Look closely at th dash lights when you shut off the car normally. You will see the key symbol flashes. What you describe sounds like the car shut off due to thinking the key was switched off.

Also, the steering wheel will not lock unless you turn the key switch full anti-clockwise (to where you could remove the key)) so no concern there unless your switch was defective and turned itself off and had the weight of the keys turn it off.

Thanks @jwzimm, I'm have a look tonight and report back

How much junk is on your keychain weighing it down?