Perforations differ depending on the printers, so to keep this section simple I will list them, and not go into to much detail. All are listed to the nearest half perf.

               Printer                             Type                           Perf

Imperforated:

Some stamps were issued with either one or more sides completely imperforated. These are normally from booklet panes that have been guillotined. 1st class, 2nd class, anniversary and numeric stamps exist.

All of these stamps are collectable and fetch good prices. There are many combinations that were released by several different printers. (Remember to look out for notched and short bands also)

Trimmed Perfs:

 Some booklets and coils contained stamps with trimmed perforations, these are normally classed as damaged, although they are still collectable, and at modest prices. Stamps such as the half pence side band from the Wedgwood booklet can be obtained a lot cheaper. This allows you to fill some of those elusive gaps without spending a fortune.

Errors:

Imperforated stamps also exist through printers error, some are only partly imperforated, but complete imperforates exist, these stamps are quite rare and highly collectable .

Elliptical perforations:

Introduced to the Machin series in 1993. The ellipses help to deter any attempts of forgery. The elliptical holes are on both vertical sides of the stamp, roughly three perforations in length, they vary in shape from one printer to another.

Harrison and Walsall printings are normally ellipse one, these are wider than some of the Questa Printings referred to as ellipse two. Stamps from Questa have been found with both types of ellipses.

It has been said that ellipse 1 resembles a the shape of a rugby ball and ellipse 2 a sausage or cigar shape. These have also been described as ellipse R (Rugby) and ellipse S, (Sausage). Combinations of both types of ellipses have been reported on the same stamp, also they have been discovered inverted (at the top the stamp). Because of the rarity of these particular items they are beyond the scope of most catalogues, but it is worth a mention. One never knows ones luck, a find like this could be worth a small fortune.