I planted a Victoria Plum tree 3 years ago, but haven't had any fruit yet. It had quite a bit of blossoms last year, but no fruit, and very few blossoms this year. Any advice please.
I have a plum tree (not a Victoria but a similar variety). After about 4 years in the ground (I planted it as a 2/3-year-old fan) I had a single plum. The next year I had several kilogrammes. Since then nothing for about 5 years -- not even blossom -- until this year, when I got loads of blossom and the fruit are starting to grow. My pruning has been rather haphazard (space constraints are important).
It's very easy to get unlucky with the weather with plums. I wasn't paying attention at first, but I'm sure in some years the buds have been killed by frost. A late frost after a warm spell could be the issue, which we just avoided this year.
Another factor to watch out for is birds eating the buds. We didn't get any bullfinches in our garden this winter/spring, and we often do. They eat buds, as do parakeets.
Plums aren't too fussy about soil so long as it's not flooded or parched. If it's unhappy you're more likely to get a poor crop or fruit that don't ripen, and the leaves should give you a sign as well.
Three years is very young for a plum tree. I know many nurseries will tell you that their plants will begin to bear fruit in 3-5 years, but in my experience, 6-7 is more likely. It is also not uncommon for an immature tree to flower for a year or two but set no fruit. I'm afraid the only thing you can do with a young fruit tree is wait.
While I'm quite certain that age is the major factor for you, a cold spring can also prevent a flowering tree from setting fruit. The blossoms can be damaged by frost, or can simply go unpollinated if it is too cold for pollinators to fly at the critical time when the tree is in flower. Again, there is very little you can do when this happens, but you could try covering the tree at night if there is a frost when it is in bloom (depending on the size, of course) and hand pollinating.