Dismissal on the grounds of conduct is different to capability as this is a matter of choice by the employee, they refuse to do the work that was reasonably requested of them or refused to behave in a reasonable professional manner as required by their employee contract.
Normally a single act of misconduct would not be grounds enough for a fair dismissal. Many employment tribunals view dismissal as something that should not be done lightly and in most circumstances would expect an employee to be given a second chance.
An employee should be given a warning and their conduct should be managed through the disciplinary process, explaining that they are risking dismissal by their actions. This should be given in writing and kept as a record.
You can fairly dismiss an employee if they have been specifically told that any repeat of the behaviour(s) will result in dismissal. The employee has chosen to act this way knowing the possible consequences, you will still be required to show that this was reasonable but as you have written documentation then this will be easier to show to a tribunal.
Gross Misconduct however is a type of behaviour that is seen to be wholly unacceptable, if any employee has behaved in this way, they can be fairly dismissed immediately, without notice. Examples of Gross Misconduct could be theft, violence at work or harassment. As an employer you would need to demonstrate that the behaviour was so unacceptable that the employee has broken his contract.
To ensure that the any dismissal is fair, you must demonstrate that you have followed a fair process, simple HR have the expertise and all the documentation required to manage an employee through a disciplinary process.
If you require more information about dismissal or employment tribunal please contact us at firstname.lastname@example.org or on 01506 238745.