What is a constructive dismissal?

A constructive dismissal is where an employee resigns because of some action by the employer which causes the employee to believe that continuation of employment is impossible.

This action could be a detrimental change in the contract of employment, (although it has to be a fundamental change), or a refusal to improve intolerable working conditions.

Constructive dismissal cases are hard to win, and unless your conditions are absolutely intolerable you should take early advice before walking out on your job.