kev100- It was a genuine question that I have always wondered about, and finding things like that is what this site is for. So please, if you're gonna post answer the question, don't offend the person who asked the question, that's just immature. Remember, a man who asks is a fool for have 5 minutes, a man who doesn't is a fool for the rest of his life.
Most of the UK potato crop was harvested in the autumn, and some of it would remain stored up until the next crop was picked in the following year.
But some potato crops in Malta and Cyprus were ready as early as May, and would be imported to the UK. Greengrocers would advertise them as 'New Potatoes' to differentiate them from the last year's autumnal crop that had spent months in storage..