Its anticipated effects may be seismic, but they are, as yet, unquantifiable. Despite invoking article 50, the UK remains a member of the EU, and is likely to do so until 2019. 
Business Relationships with Europe
Back in February 2017, even before Theresa May triggered article 50, 58% of FTSE 500 senior executives responded to an Ipsos MORI poll, with the view that the decision to leave the EU was a negative one for their business. An even greater percentage, 66%, expected a further deterioration in the business situation over the following 12 months. 
Meanwhile, there is evidence that the weaker pound is pushing up business costs. Statistics from the Office for National Statistics point to an increase in import costs, caused by a falling exchange rate.
Free movement of workers is an additional worry. Many businesses rely on skilled labour from elsewhere in the EU. In the financial services' sector, passporting rights continue to cause concern. Many large organisations headquartered within the City of London are formulating, or even expediting, plans to move sections of their business to other EU cities. Equally, various EU countries and cities are lining up to lure European organisations currently located in the UK. 
Other types of business also rely heavily on an EU workforce. The sandwich and coffee shop chain, Pret A Manger, which employs large numbers of non-UK EU citizens, has announced plans to target new recruitment drives at UK school leavers. The consulting firm, Mercer, is among those that have warned UK businesses to expect growing gaps in the labour force as a result of the Brexit effect.
Travel within the EU for UK Citizens

At present, there are many speculations surrounding how Brexit may affect travelling in the EU for British citizens. It depends largely on any deal the UK manages to reach as part of the exit negotiations. The best case scenario would see UK citizens facing nothing more than a change to the colour of their passports. The worst case scenario would involve applying for visas before travel, and significant rises to the cost of holidays and other travel.
Living and Working within the EU
As with general travel within the EU, UK citizens currently face no change to their existing abilities to live and work elsewhere within the EU. This is highly likely to change, with potentially difficult consequences. As is widely reported, the rights and status of those UK citizens now living and working in other EU member states are potential bargaining tools. Consequently, clarification of their status is unlikely to happen soon. Those already eligible for residence, or nationality, of another member state might want to expedite the process. Even if they retain these rights after the UK's exit from the EU, the rules may change. In Germany, for example, EU nationals are allowed to apply for German nationality whilst also retaining their current nationality. Conversely, dual nationality is not permitted for non-EU nationals. This means that any Briton waiting until after their country's exit from the EU to apply for German nationality is likely to have to give up their British nationality. Of course, such rules could change as a result of Brexit negotiations, but anyone seeking certainty for their own situation might want to work within the existing rules while they still have access to them.