It appears that the nay sayers on here are the types who only fly on perfect zero wind cavok days after doing a risk assessment...
If you are referring to me then perhaps you should know I'm currently an instructor flying about 900 hours a year. I've ferried planes across the atlanic, across europe to the middle east and down through Africa in my past. I've flown in conditions some of you couldn't even imagine.
That said, if there is a rare event of a volcanic ash plume overhead with unknown density and the authorities have decided to close UK airspace I would use common sense and not fly myself. It has nothing to do with skill or experience, it would be reckless to endanger those people on the ground considering the advice from the Metoffice. By the time you would know of problems flying through ash it would be too late.
The ash plume you see on TV is a few hundreds metres across at the volcano. By the time it reaches the UK that has spread to a few hundred miles across. The contents of the plume are the same but why do some people on this forum still think you would see the ash when its spread that far apart?