There are leeks and there are leeks and each have they own method of growing.
I was brought up here in the north to think in terms of basically two types of leeks namely; Pot leeks and Blanch leeks and the method of growing these is different to what most gardening books seem to give.
Blanch leeks are sometimes split into two categories (Blanch & Intermediate) subject to length.
For exhibition purposes leeks are divided into three categories: ;
Pot not more than 6 in (15 cm) from base to button.
n.b. the 'button' is the 'V' formed by the first two leaves (flags) above the base.
In judging terms;
Meritorious leeks; are firm solid heavy leeks with unbroken clean unblemished skins, that are uniform in size, have straight barrels and fresh coloured foliage.
Defective leeks; may be soft, thin, split buttons, too long-shafted i.e. over 6"(15cm). There may be evidence of seed heads, disease, mechanical damage and malformation.
Note: The National Pot Leek Society give additional points for volume or cubic capacity measured on volume of blanched shaft to tight 6 in (15 cm) button (i.e. from basal plate to lowest unbroken leaf, including the veil where present and around the barrel).
One point for every 10 cu in (164 cu cm) and decimal point for part of 10 to a present maximum of 20 points or 200 cu in (3277 cu cm).
Tables for the calculation of cubic capacity are obtainable from the Secretary of the National Pot Leek Society.
Intermediate not less than 6 in (15 cm) and not more than 14 in (35 cm) from base to button.
Blanch more than 14 in (35 cm) from base to button.
n.b. the 'button' is the 'V' formed by the first two leaves (flags) above the base.
In judging terms;
Meritorious leeks; are solid, thick, long-shafted, well-blanched leeks, tight-collared with clean, spotless skins and no tendency to bulbing.
Defective Leeks; can be soft, thin, tapering, short-shafted, imperfectly blanched, discoloured or bulbous.
So as you see the type/s most people grow doesn't fit into the above, so for comparisons sake I think I will invent a new term and call the dibbled types 'culinary leeks' this is not to say that you can't eat Pot & blanch leeks indeed you can.
Cultivation;Culinary leeks; These as mentioned are dibbled into the ground for one reason only and that is to blanch them, theoretically the deeper they are the more they are blanched.
So one could say that it is quite possible to meet the above criteria at least for the 'pot leek' category
Having said that their diameter can be somewhat restricted depending upon the soil they are planted in, i.e in light soils they may of a greater diameter than say those grown in a heavy clay soil.
Plus you would have difficulty growing them to a uniform 6" (15cm)
Pot, Blanch and intermediate types are generally grown in beds specially prepared for them with copious amounts of humus making material added.
After germination they are pricked out at the 'crook' stage into 3" pots and grown on quite often under heat until they are ready for planting out.
Crook stage is seen as a natural bend in the leading seed leaf reminicent of a shepherds crook.
At planting out time they are planted out to the same level as they were in the pot, i.e. they are not sunk into the ground, and the leaves are not cut/trimmed.
As they are grown each pair of leaves on the pot leeks are supported to ensure that they don't crack/kink.
Blanch leeks are grown in pipes preferably earthen ware as these don't sweat as much as plastic and the leaves are also supported.
The plants are never allowed to dry out and are always well fed very often with the growers own recipe.
So now do you see why I don't grow my leeks like the 'gardening books' say?
The following pictures should give you a better idea of what I have tried to describe.
Pricked out; 
Culinary leeks;
Pot leeks;
Blanch leeks;
