Like every British tank since the Centurion, and most other British Armoured Fighting Vehicles, the Challenger II contains a built-in boiling vessel (BV) also known as a 'kettle' or 'bivvie' for water which can be used to brew tea or produce other hot beverages. The BV is a design requirement for all armoured vehicles of the British Armed Forces, and a feature almost unique to the armed forces of the UK.
We may not be a military superpower any more, but at least our Main Battle Tank has adequate tea and coffee making facilities as standard.