Specifically about India:

• Shashi Tharoor, Inglorious Empire: What the British did to India, or
• Priyamvada Gopal, Insurgent Empire: Anticolonial Resistance and British Dissent, chapters 1, 4, and/or 5.

There’s a ‘great’ short book about British colonialism: Peter Fryer, Black People in the British Empire. I say ‘great’ because it’s informative. It’s not for the faint hearted. The surprising thing is how many brutal crimes it’s possible to catalogue in less than 130 pages. Pages 17–24 and 107–17 focus on India.

If you want to look at the connection between law, property, and colonialism, try Brenna Bhandar, Colonial Lives of Property: Law, Land, and Racial Regimes of Ownership.

Kwame Nkrumah’s Neo-Colonialism: The Last Stage of Imperialism is relevant, but it may be more helpful to establish the facts of what happened before the time that he is talking about, depending on your group.

Depending on the politics and how ‘academic’ your group is, a book like Alice Procter’s The Whole Picture: The Colonial Story of the Art in our Museums & Why we Need to Talk about it could be a good place to start.