Since the general election last July, much of the attention in UK employment law has been on the changes being brought into effect by the new government. However, another, longer standing influence continues to impact the way cases are being determined and will likely do so for some time to come.

After Brexit was properly implemented around five years ago, while the government put in place measures to protect the existing European Regulations and Directives – the Retained EU Law, which was pretty much a cut and paste job – the one area that provided meat to the bones of that legislation was the case law that came from the European Court of Justice (ECJ).

Now, that no longer applies, with British courts not required to follow the earlier ECJ decisions. And, broadly speaking, it would be fair to say that the laws passed by the EU were what many would consider ‘left of centre’. In other words, they tended to side with workers’ rights and protections, rather than employers, with the ECJ decisions tending to reflect that pro-worker stance.

In practice, this means that 50 years of legal history that employers could rely on to determine the strength of their case has almost effectively been wiped out. When pursuing a case, even if you have a supporting ECJ decision, the safest authority might be an historic British case.

If there is no UK precedent, then employers need to be prepared to take their argument to the Supreme Court. Doing so can be mightily expensive and the outcome may be massively uncertain. That presents a huge risk to any business and, unless a similar case has already gone through the same process, while you can have an educated guess, you just don’t know how the court will interpret the situation put before it.

A recent case demonstrating the potential disconnect between pre- and post-Brexit rulings involves a school worker in Gloucestershire, who was sacked after taking to social media to criticise how children were taught about same-sex marriage.

Based on historic cases, it would be reasonable to believe that decision would have stuck under European law. But, after an appeal process that took six years, all three judges involved in the latest instalment ruled in her favour, deeming that she was unfairly dismissed. The case is widely seen as a landmark freedom of conscience trial, setting a judgment by which other cases will be measured. 

With UK courts having more control of decisions, there could be more determinations like it in the future. Areas to watch that were previously considered very settled could be the likes of cases involving holiday pay – which has historically been calculated differently in the UK – and Transfer of Undertakings (Protection of Employment), much of which relied on European legislation.

By erasing half a century of legal history in the wake of Brexit, there has been an element of the baby being thrown out with the bathwater – and, with that, there is a paucity of information to realistically say what the outcome of legal proceedings could be. So, if you are a business taking a case to tribunal, make sure there is a body of UK evidence for the outcome you want – or be prepared for a potential shock.

Graham Millar is an employment law partner at Gilson Gray