General is the highest rank achievable by serving officers of the British Army. Wikipedia

Highest military rank of the British Army and the Royal Marines Wikidata

The holder of a senior military title, originally designating the commander of an army and now a specific rank falling under field marshal (in the British army) and below general of the army or general of the air force in the US army and air forces. Wiktionary

Military rank. Wiktionary (translation)