Why did England and France support and pursue a policy of appeasement?

Despite the fact that in Europe the strength of Germany gradually increased and the Nazis came to power, England and France continued to remain neutral. They believed that it was not worth defending the terms of the Versailles agreement so fiercely that because of this their citizens died in wars. Thus, Germany was able to carry out an “lock-out” of the Czech Republic and capture other countries. But nevertheless, when German troops invaded Poland, the Allies could no longer sit and calmly look at such arbitrariness and declared war on Germany.