Back in the early half of the 20th Century, a soldier would be issued with two pairs of Ammo boots. One pair would be double soled and bulled as his best boots, the other pair would be greased and waterproofed for use in the field. The boots were ankle height and reasonably well made out of good leather, but of course were too low to offer much waterproofing and thus were generally supplemented by gaiters, anklets or puttees.
At some point in the late 1950s or early 1960s, some genius within either the Army or MoD decided that our boots needed updating but, instead of going for a higher leg design, with sewn in tongue, which offers great waterproofing and protection advantages and were in use in just about every other army in the world from Andorra to Zambia, decided to keep the basic shape of the antiquated Ammo boots but fit them with a rubber 'Direct Moulded Sole'. Oh yes, and they made them out of lower quality leather as well. Thus were born Boots DMS.
The suggestion that anyone thought that Boots DMS were a good idea is beyond belief. For a start it meant that, in a modern, late 20th Century army, every soldier had to spend a couple of minutes every morning wrapping a brown wool puttee around each ankle. Much more seriously however, during the Falklands Conflict in 1982, trench foot reared its ugly head again after a sixty-five year absence, because troops were unable to keep their feet dry for weeks on end as the result of wearing a crappy, non-waterproofable, ankle boot. Many squaddies during the Falklands War went round nicking boots from dead Argies who had more durable footwear with a higher leg.
In fact by then a replacement was already in the pipeline and in 1984 issue began of the Boot Combat High, or 'BCH'. The first of these were pretty good: sturdily made of strong leather, but they did have several drawbacks. For a start, the design was such that for some soldiers, creases in the rear of the boot put a great deal of pressure on the Achilles tendon, leading to acute tendonitis and other lower leg injuries, particular when they were used for running; they were also difficult to break in and could cause severe blisters for the unwary.
Several minor redesigns followed, and soldiers - and particularly recruits - were generally discouraged from doing any kind of PT whilst wearing boots. However, simultaneously, as manufacturers sought to maximise profits and MOD tried to cut costs, quality of manufacture dropped to the extent that nowadays, whenever the British Army goes on a major operation, there appears to be a COTS purchase of suitable well made footwear such as, for example, Danners or Matterhorns, whilst the issue combat boot - which is currently beset by problems with the rubber soles disintegrating or falling off - are basically used for Barrack Dress. Anyone with genuine problems with Army footwear/ their gait (way of walking) can apply for more supportive/ higher quality boots on issue. See: problem feet
All in all, the saga of British Army boot procurement is pretty pathetic: that we can consistently buy such rubbish, thus inevitably incurring far higher costs than would be necessary in buying one of the many excellent commercial products, is astonishing but symptomatic of British Defence Policy. At a rough estimate, 50% of British soldiers wear boots they have bought for themselves when on operations or exercise.