Well, I thought so, enough even to mentioned it to the missus. My 3 yr old Greek Yellow, which is in a 5 gallon pot, currently has figs on it that are roughly 0.5" across and 3-4" leaves. Yet my unidentified 10-12 yr old 'Tasty but Fussy', which is in the ground, still has nothing to speak of, except maybe a few sub pea-sized fruit.

Well, I knew it was fussy (hence its nickname), but even I didn't realize it was that fussy. Bearing in mind that TbF is a 'native' of this country (as in, purchased from an English nursery), and my GkY hitched a ride on the back of a lorry all the way from Greece (clever those Gk fig trees), I find this disparity between the two all the more surprising.

I even have hopes of getting some ripe fruit from it for the first time this year. Now that would be something. But until it's identified, I don't think I could have picked a more appropriate nickname for my TbF.

Does anybody have a possible explanation? 

In ground tend to break dormancy of pots, the pots warm up the roots much quicker than the ground does.

Ah, so. Why didn't I think of that? But then, that would imply that I should leave my GkY in its pot permanently if I want to improve my chances of getting ripe fruit.

That would be ideal, if only it were practical. Maybe that solar-powered greenhouse idea is the only real long-term solution after all. 

Not sure about hot climates but here in ours a potted fig will beat out inground breaking dormancy every time.

@ Martin - I would hardly call SE London's a hot climate. We get exceptional summers maybe once every 6-7 years. The last few such were 2013, 2006, 2000, 1995, & 1990. But yeah, thanks to Chivas post above, I now get why my GkY seems to have stolen a lead on my TbF.

I'll be layering GkY shortly (also in demand from UK forum members, etc), thus bringing it back down to a much more manageable size in terms of 'volume'. The temptation then will be to leave it in the pot instead of grounding it if that means a better chance of ripe fruit. Is that what you would do?

You could keep it in the pot (largest you care to handle) and root prune every few years.

Thanks for the suggestion Philip, but transferring it to an even larger pot carries its own problems, over-wintering being one of them if the temp. drops below zero. Watering while we're away is another - my son is not totally reliable in that area.

I suspect that there's no real alternative to 'grounding', possibly accompanied by some kinda modified form of cloche to extend the ripening season. If my idea works, I might post it via a bump on this thread. 

I forgot to mention 2003 in the above sequence of exceptional summers, mainly coz it falls outside the general pattern. We recorded our highest temp in that year - over 100F on the 10th Aug. What a year that was for figs & loquats. Even tho I can't stand that kinda heat, I hope to see it again just for the fruit that it produces.