Susan Sheehan, Pete Sanderson, Ann Harris. This project set out to identify criterial features of written and spoken English at C1 by examining test data to establish which of the language points included at C1 in the British Council – EAQUALS Core Inventory for General English (the Core Inventory) were produced by the test-takers. The test data were also examined to see if there were recurring language points which had not been included in the Core Inventory.