Regiment system - further comment:
Traditionally the regiment in the UK is seen as the parent cap-badge, under which sit a number of battalions. Officers and serving soldiers may transfer between battalions but never normally between regiments unless on course or to a specialist unit (UK SF).
The UK is moving once more towards a large regiment system, with 2 plus battalions (regular and reserve) come under a single administrative regimental HQ and cap-badge. The reason for this change is partially due to the dropping of the arms-plot system, where battalions where re-rolled every few years (armoured infantry based in Germany to light infantry based in the UK every few years). Now we are seeing battalions moved to new permanent UK locations in super-garrisons.
Because the UK is sending it’s units unaccompanied (dependents remain at home) overseas on active service more and more, larger regiments, with a common history and traditions can fill gabs in manning (short-term inter-battalion transfers), maintain a degree of stability, provide mutual support to families left behind and run a more efficient organisation under the new ‘large regiment’ system.
The following is an example of how the LI and Green Jackets have been cap-badged under the new expanded Rifles Regiment, which now has seven battalions / sub-units:
http://www.army.mod.uk/infantry/regts/the_rifles/regiment_today/battalions_locations/index.htm
History and tradition pays a very important part in UK regimental life, with strong allegiance to the colours, queen and traditions. Hence the desire to be always associated with a regiment for your service life, whether it be the Guards, Para’s or Ghurkhas.