Is an employee who does not submit a written grievance barred from bringing a tribunal claim based on their complaint?

No, there is no statutory procedure requiring employees to present a written grievance to their employer before bringing a tribunal claim.

However, a failure by an employee to raise a grievance may still be relevant to a tribunal claim based on the complaint as the Acas code of practice on disciplinary and grievance procedures provides that, where it is not possible to resolve a complaint informally, employees should raise a grievance formally and in writing with their employer. An unreasonable failure to comply with the code may result in a reduction to any compensation that the tribunal awards to the employee of up to 25%.