Inspired by works like Code Geass, Decades of Darkness & Puritan World. In this world Oliver Cromwell is never born and the English Civil War goes differently. King Charles remains in absolute power for longer before several decades later a second war deposes him and establishes a republic for a short time. A coalition of Catholic nations invades and conquers the British Isles whilst forcing the Protestants and Parliamentarians to flee for the colonies. There with a more supportive colonial power-base they break off through a war of independence. The New Commonwealth floundered for a few years after its development before the resident Lord Protector took most of the power and eventually declared himself Emperor. The Empire of New Britain rapidly spread across the continent with great zeal and vigour.
The Empire of New Britain is the world super-power covering over a third of the Earth's surface. The Empire now known as the Reunited Empire after the War of Expansion reclaimed the British Isles is an overextended, unwieldy entity but definitely a powerful one. Whilst no longer a slave owning society and definitely anti-discrimination towards any race they are a religiously intolerant, repressive theocracy. Systems of Moral Law keep strict social codes and mannerisms within the Empire and supposedly assist in the conversion of imperial subjects not already committed to the acceptable denominations within the Empire. Despite the (supposedly) constitutionally restricted power of the Empire the Church is an enormously powerful entity within New Britain controlling media, education and most social events across the Empire. Festivals are strictly illegal and whilst some laws and restrictions have been relaxed in the past few decades, open signs of festivity are vilified by the public. Despite the Moral Law however there are numerous dens, speak-easys and black-markets in every imperial city that are often ignored by imperial officials.
New British colonies are prime examples of the colonial stereotype of abuse. Indigenous populations undergo enforced conversion programs and force-draft industrialisation in order to make them productive imperial subjects. Racial discrimination is no longer a policy in the Empire and now it no longer matters what your race is but now what your creed, money and status are. Whilst officially a constitutional monarchy, the power of the Emperor is still incredibly significant in government. However his power pales in comparison to the Church's and to the powerful corporate families and associated groups. The army has also become a a significant factor in government as the Empire struggles to assimilate their truly foreign conquests.
The War of Expansion managed to unite much of Europe during the invasion by the New British. Their mutual support, partisan activity in occupied territory and their use of submarine warfare to target New British logistical lines managed to stop and almost reverse the New British conquests and eventually a treaty was drafted between the Empire and the New Coalition.
France is still technically the figurehead of the Coalition and has benefited the most having received reconstruction funds from their allies for the New British invasion and also for the colonies they re-appropriated from the British. France is now a strictly constitutional monarchy with the power now strictly in the hands of the rich commoners rather than the nobility. France is the cultural centre of the world with the expansion of the movie and television industries seeing a massive proliferation of French made films and programs. France is more militant than OTL and imbued with a confidence from their victory over the enormous New British Empire that they continue to carry into their future. French colonies are fairly difficult regions due to the control of mercantile and corporate families that exploit workers and resources for profits.
The Dutch did far better than OTL and due to being the most powerful of the (non-Austrian) German states was able to rally them together after a war with France in the 19th Century. The Dutch Kingdom is a constitutional monarchy as well and the official leader of the North German Confederation. The Confederation is a cosmopolitan society due to the recent influx of Indonesian and Khoisan culture from the colonies along with the immigrant population. The Confederation of The Rhine is a very loose construct that works hard to keep the delicate balance between the Protestant North and the Catholic South in place. Prussia did not do anywhere near as well as OTL but managed to make something of itself overseas after a personal union with the Netherlands.
Russia is the other massive Empire in the world and like New Britain is an overextended, unwieldy nation. Russia is a strictly Orthodox nation but not to the same degree as New Britain. Russia's most recent expansion phase was during the Turkish War where Russia (and several others) invaded the Ottoman Empire in the 1870s and managed to conquer Mesopotamia and a strip of territory from Anatolia. Iran and Northern India were added to Russia during the war as well and finally provided numerous warm water ports for the Empire albeit through Muslim ruled territory. Russia has faced problems with the number of angry Muslim groups in their Southern territories and a campaign of pacification has been ongoing for several years with mixed results in regions. Russia is no longer as expansionist as before now that the problems of its size have emerged but they are casting glances towards China the Marathans and the still unconsolidated New British territories of East Asia. If they can sort out their problems soon then there is opportunity especially now that their new rail-road system is up and running on time.
China did not suffer as bad an experience as OTL but the Qing Dynasty was overthrown by a previously insignificant and progressive military family known as the Lihua family. After claiming the title of Emperor the Lihua family began implementing new social and economic reforms that saw an explosion of industrial activity and construction through the Mid 20th Century. China is still backwards today with a large peasant population but they are a player on the world stage. The invasions of Japan and Indochina have also awakened China to the dangers of the New British and the Emperor and ruling council have begun a new program of infrastructure construction and militarisation to prepare for the next New British expansion phase. China is still technically a absolute monarchy but the Emperor's power is wrapped up in tradition and bureaucracy and a representative Council handles most day-to-day matters.
Technology is at the 1940s-50s level though there are no nuclear weapons. Cars and televisions have only been main consumer goods for 20 or so years and jet engines have only just entered their test phases. Most travel is by sea with Zeppelins making up most commercial flights (military Zeppelins were shot down and discredited in the European War). Societies are also more conservative and vary from the restrictive New British to the almost indecent 'flapper' society that has emerged in Spain's young women. Culturally there is an emphasis on science fiction with stories of space travel, giant robots and mad scientists being very popular (most are barely legal in New Britain but get published anyway). Totalitarianism is a major issue and with the big scare being on theocratic rule as Russia becomes more religiously reactionary no-one wants the worlds other super-empire turning fanatically religious. This worlds version of George Orwell wrote 1984 with the Big Brother posters featuring men in vestments.