How is the united kingdom's government different from Germany's government?

There a several differences between the UK government and the German government. Probably the most significant is that Germany is a federation, whereas the UK is a unitary state. The upper house of Germany's parliament, the Bundesrat (federal council) consists of the appointed representatives of the Länder (states), whereas in the UK, the House of Lords consists of Lords Spiritual and Temporal, that is, representatives of the church and the peerage. Also, the powers of the devolved governments in Scotland, Wales, and Northern Ireland are entirely granted by the Parliament of the UK, the German Länder are sovereign, and thus free from federal interference in their jurisdiction.

Another key difference is that the UK practices the principle of parliamentary supremacy, whereas Germany practices judicial review. This means that, in the UK, parliament is entirely responsible for ensuring the constitutionality of its own actions, whereas in Germany, this function is served by the courts.

A final difference, more of form than function, is that, while both the UK and Germany follow a parliamentary system, the UK is a constitutional monarchy, while Germany is a republic. Whereas the UK has a hereditary head of state, Germany has an elected one. Because the German President has an electoral mandate, he or she is more likely to use the reserve powers, and as a result, these powers are more restricted than those of the Monarch of the UK.