Unshod pony has grown a flare?

[Mince Pie]

Had pony over 6 years, came with the most awful shoes on all 4 feet - none matched or fitted so promptly removed and not replaced. Had one set of fronts last year but otherwise always unshod with good feet.
Recently I have noticed a flare on the inside of his front left foot and he has a reluctance to bend left (although he has had this before due to me being wonky with a back issue), what does the flare mean? He's sound as a pound on the lunge on a hard surface and in the school.

 

[Gloi]

If it's just recently started to develop then he's changing the way that limb moves. The flare on the inside means he is landing with more weight to the outside of that foot. If this is a new thing for him there is probably some problem higher up that limb causing him to move like that, or something to do with his back because of your unevenness you mentioned altering his gait.
Track down the source of the problem if you sort that then and the flare will probably correct itself.

 

[Mince Pie]

He had a full MOT about 6 weeks ago by the vet and nothing was found, he had thrush in that foot which has now cleared up could that be it? He's about to be turned out for 3 month as I'm having a small operation so will have a look at it when I get back.