Complex sentence: He resigned from the army under threat of discharge in 1999 at the rank of Major after breaking Queen's Regulationsand served as the Public Affairs Officer at the Commission for Racial Equality (Scotland).
Split into simpler sentences: He resigned from the army under threat of discharge in 1999 at the rank of Major after being found to have broken "Queen's Regulations". He then worked as the Public Affairs Officer at the Commission for Racial Equality (Scotland).