Social media sites encourage people to upload photos of Christmas work parties, and Simon Gilmour, an employment law partner at Shakespeares’ Stratford office, is reminding employers to consider social media policies over the party season.

Because many employers now allow staff to use their own smartphones for work and home, the lines between people’s professional and personal lives have been blurred.

He said: “The way people share experiences when out and about socially has been transformed by the introduction of smartphone applications such as Instagram, which can share photos across social media networks in a matter of seconds.

“As a consequence, The reputational risks are much greater for employers who are ultimately responsible for any inappropriate conduct that could arise during a works party for example.”

Mr Gilmour thinks employers should go further to warn employees about the consequences of social media misuse ahead of the festive season.

He said: “Employees should be informed that social media mentions will be monitored over the Christmas period and defamatory comments about the company will be grounds for disciplinary action.

“At this time of year, employers may be worried about being seen as killjoys but it is in everyone’s interests that workplace policies are set out clearly, transparently and are properly enforced.”