Shows you how standards have dropped. When I joined it was:-
Direct entrant ATCO Cadet - 5 x GCE's of which two must be 'A' level preferably maths and english
ATCA to ATCO Cadet - 5 'O' levels plus one 'A' level plus one year as an ATCA (ATSA nowadays)
or - 5 'O' levels and two years ATCA/ATSA