This paper addresses the issue of the development of FOR DREAD THAT – a negative purpose subordinator in the history of the English language. The theoretical foundation of this work are the mechanisms of grammaticalisation suggested by Heine and Kuteva in many works of theirs. The gathered material shows that the development of this relatively rarely used subordinator constitutes a case of a typical grammaticalisation whose rise might have been the result of analogy with FOR FEAR THAT.