It is very unlikely that any exit from the EU would cause widespread changes to employment law overnight – the majority of the employment law we have that comes from the EU would still form part of UK law unless and until it was amended or repealed.

This is because legislation from Brussels comes to us in two main formats: regulations and directives. Regulations made in the EU are directly applicable and automatically binding in the UK from the day they are made. Regulations in this field are comparatively rare – one example is Regulation (EEC) 1408/71, which deals with the application of social security schemes to workers and their families moving within the EU.

The majority of EU law relating to employment comes to us as directives, which contain objectives to be achieved by a given date. The individual member states must then draw up national legislation to conform with the directive within a certain time frame. In the UK, directives are usually implemented by statutory instruments and occasionally by Acts. The terminology can also be confusing – what we in the UK call the TUPE “Regulations” 2006 and the Working Time “Regulations” 1998 actually come from the Acquired Rights Directive and the Working Time Directive, and are not EU Regulations at all.

In recent years, the Coalition and Conservative Governments have been trying to remove what they call “gold-plating” of legislation – removing from the statute book those aspects of employee protection that go further than the basic objectives required by the original EU directives. These provisions were largely implemented by the previous Labour Government. For example, the Working Time Directive gives full time workers 20 days of paid annual leave, while the UK Working Time Regulations provide an entitlement to 28 days. The TUPE regulations also go beyond what the EU requires, with the addition of the concept of a service provision change, as do the Agency Workers Regulations 2010.

It is likely that if the UK did leave the EU, this gradual process of amendment and/or repeal would continue and could be significant, being dictated by the political aims of whichever political party was in power. Areas likely to be the focus for change include agency worker rights, annual leave, collective redundancy, discrimination legislation, part-time worker rights, fixed-term worker rights, paternity, maternity and parental leave, and protection of employment following the transfer of an undertaking.

An immediate large scale repeal of the employment laws that originated in Brussels is very unlikely, as that would cause massive disruption and cost. The impact on employers of a restriction on the free movement of workers is likely to be much more immediate and is covered in the corporate immigration section.