Prior to today's pootle I was checking my tyre pressures and lookee what I found when looking at my rear!
There is another smaller gouge on the other side of the tyre too so I must have hit something! I've got no idea or any recollection of hitting anything but it looks quite nasty.
The tyre does appear to have a very slight leak although I'm not sure if it's due to this damage or one of the many other nicks (amazing how much damage a tyre picks up with no issues). Anyway, what do you reckon - keep an eye on it and keep riding or think about replacing (I've had 10,000km out of this tyre so far)?