The British Army and Royal Marines got involved with countless actions, large and small, all over the world. The control of the seas meant that British military power could be projected to all four corners of the globe. Generally, the British government attempted to avoid military campaigns and conflicts. They were expensive and they could not always be assured of the outcome. However, a decisive flexing of the muscles early on could head off more costly, long running commitments. The Army did not get a choice of which campaigns it would embark upon. The decision to commit military forces were often undertaken by British government representatives on the ground or were in response to hostilities breaking out in local populations. The Army's principle job was to maintain order and remove hostile forces. Of course, this could become more complicated if the forces were rival European powers or their proxies. A good example of how European conflicts could spill over to the wider colonial world was the Seven Years War - which was probably the first true world war.
What is surprising, is how small the British Army was for garrisoning, defending and policing such a vast Empire. Local forces could sometimes be raised, particularly in the settler colonies like Canada or South Africa, but generally the Army had to rely on technological superiority and a confident officer class. The Royal Navy could also be relied on to support local difficulties by lending naval personnel or moving reinforcements to the conflict quickly and without interruption: Control of the seas really did translate to control of much of the land.
It was difficult to decide how to split the world up in terms of military campaigns. The British were heavily committed in some zones and not so much in others. Asia was a real problem in size and scope and so has been split into India and the North West Frontier, the Middle East and the Far East. South and North America have been joined together. Use the menu to the side to locate the campaign that you are interested in finding more about. I am trying to add more and more information about the many conflicts, but this will take time. It should also be noted that this site primarily intends to focus on colonial conflicts. This means that the larger European conflagrations such as the Napoleonic and World Wars are not being prioritized for coverage. Besides, it is felt that these wars are already widely covered on other sites on the internet. Having said that, some of the smaller 'colonial' aspects of those campaigns may well sneak their way in. If there is anything that you would like to see added or if you would like to suggest amendments or submit your own information or details about a campaign then please feel free to email me at firstname.lastname@example.org