St Mary's finest puzzlers solve the GCHQ Christmas Puzzle Challenge!

From its origins as a brainteaser written in a GCHQ Christmas card, to becoming a public competition, the GCHQ Christmas Challenge has become a well-known symbol of code-breaking, lateral thinking and cryptological potential. In its current, modern form, it encourages students to explore the STEM subjects - science, technology, engineering and maths - while developing skills such as perseverance, cooperation and analytical thinking.

This year, St Mary's finest puzzlers (both staff and students) took part in the challenge, working in teams against the clock to solve the seven fiendish puzzles. Our students finished ahead of the teachers, and with two minutes to spare.

Have you got what it takes to solve this year's GCHQ Christmas Challenge?

December 2025