The Black Wednesday economic disaster in September 1992 left the Conservative government's reputation for monetary excellence in tatters, and by the end of that year Labour had a comfortable lead over the Tories in the opinion polls. Although the recession was declared over in April 1993 and a period of strong and sustained economic growth followed, coupled with a relatively swift fall in unemployment, the Labour lead in the opinion polls remained strong. However, Smith died from a heart attack in May 1994.
By when did the Tories have a comfortable lead over Labour? (If the question is unanswerable, say "unanswerable")
unanswerable