In order to sue you for breach of contract your former employer would have to demonstrate that they had suffered a financial loss caused by your early departure. Damages aren't the only thing your employer might want though. Your employer could also seek an injunction from the court to stop you from going to work elsewhere until you've completed your notice period, or for even longer if you've gained a competitive advantage by breaching your contract. If the impact of you leaving the business without giving notice is minimal, the chances of your employer suing you for breach of contract is usually low. To a certain extent, it depends on what kind of role you're in and your reasons for leaving. However, if you're in a senior position and your role can't be easily filled, or you're leaving to join a competitor, the impact on the business may be considerable and your employer may be more likely to threaten action. If you're a company director or simply have responsibility for company assets or client funds, you're also likely to have additional obligations, such as fiduciary duties, which will also affect your employer's reaction to you resigning without giving notice.