João Magueijo (born 1967) is a Portuguese cosmologist and professor in theoretical physics at Imperial College London.

This would explain the horizon problem (since distant regions of the expanding universe would have had time to interact and homogenize their properties) and is presented as an alternative to the more mainstream theory of cosmic inflation.

Magueijo discusses his personal struggles pursuing VSL in his 2003 book, Faster Than The Speed of Light, The Story of a Scientific Speculation.

In 2009, he published A Brilliant Darkness, an account of the life and science of vanished physicist Ettore Majorana.

In this book, Magueijo described British culture as one of the "most rotten societies in the world", and wrote that "When you visit English homes, or the toilets at schools or in student lodgings, they are all so disgusting that even my grandmother's poultry cage is cleaner".