Books like bartimaeus trilogy

The Bartimaeus Sequence is a series of children's novels of alternate history, fantasy and magic. It was written by British writer Jonathan Stroud and consists of a trilogy published from 2003 to 2005 and a prequel novel published in 2010. The eponymous character, Bartimaeus, is a five-thousand-year-old boisterous djinni. The story follows the career of a teenage magician Nathaniel and Bartimaeus, whom he has summoned and nominally controls, through the alternative history of the peak of London's domination as a magical oligarchy.

The series is set in London during the early 2000s in a parallel universe where trained people can summon demons to do their bidding. Throughout history, various individuals and empires have harnessed these magical forces to obtain great power in the world. The most recent nation to do this is the British empire (which London is of course the capital of) that has dominated Europe since the mid 19th century and continues to do so at the time of the story. The UK is a magical oligarchy where a ruling elite of magicians hold almost all the political, economic and cultural power.