On what legal basis may an employee be constructively dismissed? Are there any defences to the accusation of constructive dismissal?
what is the legal basis of constructive dismissal? and what are the defenses against it?
Constructive dismissal is provided both at common law (Western Excavating (ECC) Ltd v Sharp  ICR 221) and under statute through section 95(1)(c) of the Employment Rights Act 1996. This sets out that an employee is classed a dismissed when he “terminates the contract under which he is employed (with or without notice) in circumstances in which he is entitled to terminate it without notice by reason of the employer’s conduct.”
Such circumstances where the employee is entitled to terminate will arise where an employer has committed a repudiatory breach of the employment contract. In lay terms, this is a breach that goes against one of the terms of the contract. Such term may be express or implied. Unreasonable behaviour by the employer will not always suffice, however it can be sufficient so as to form the basis of constructive dismissal where it breaches the implied term of mutual trust and confidence (Courtaulds Northern Textiles Ltd v Andrew  IRLR 84 see also United Bank v Akhtar  IRLR 507).
Defences the employer can use against a constructive dismissal claim include, fore-most, establishing that the breach was not repudiatory and thus could not effect ter-mination. Alternatively, the employer may argue a waiver or affirmation of the breach by the employee (Gov.uk “Dismissal: Your Rights” (2016, UK Government) [online] https://www.gov.uk/dismissal/unfair-and-constructive-dismissal). This is effectively where the employee does not resign immediate-ly following the breach which can be taken as their acceptance of the breach.
Gov.uk “Dismissal: Your Rights” (2016, UK Government) [online] https://www.gov.uk/dismissal/unfair-and-constructive-dismissal
Courtaulds Northern Textiles Ltd v Andrew  IRLR 84
United Bank v Akhtar  IRLR 507
Western Excavating (ECC) Ltd v Sharp  ICR 221
Employment Rights Act 1996