Employees can resign at any time by giving proper notice under their contract of employment. Once a resignation has been given it cannot be withdrawn other than with the employer’s express permission, or where it was given in the heat of the moment and then speedily retracted.
Although there is no legal requirement for a resignation to be in writing, to avoid any confusion over whether or not an employee has resigned, it may be beneficial for an employer to include a clause in employees’ contracts of employment stating that resignations must be in writing.
Best practice would also suggest that the employer confirms the acceptance of the employees resignation and details any leaving arrangements, equipment to be returned, or holiday owing etc to ensure it is clear what date the employee is leaving on and what’s expected from them before they leave.