Business faces years of uncertainty and a potential shortage of skilled workers in the event of a vote to leave the EU, Weir Group has said.

The group’s general counsel Keith Ruddock told a Law Society of Scotland conference in Edinburgh said it was unclear what might be negotiated before the Brexit referendum. “My worst fear is that we will be asked to vote on a promise of what will be negotiated, I struggle to see true negotiation being achieved in the next two years.” A vote to exit would trigger a two-year notice period for negotiating the terms, followed by further uncertainty. “We are looking at a minimum of six years uncertainty going forward.....from a business point of view it will be why are we changing the pieces on the board without knowing where they are going to land.”

Mr Ruddock went on: “Stepping out of one of the world’s largest trading blocks at a time when the rest of the world is consolidating into even greater blocks feels counter-intuitive.”

He said the ability to move people within the EU was “hugely beneficial”, adding that 30 per cent of Weir’s engineers at its Todmorden plant were Polish because “we struggle to get engineers in West Yorkshire”.

Mr Ruddock said most employment law was derived from Europe, as were product labelling and safety standards which were highly useful to business. “”Of course the EU is frustrating and difficult at times but what it does is achieve consistency in some very important areas.” He also questioned whether inward investors would choose an exiting UK as a base in Europe.

Charles Livingstone, partner at Brodies, said a Brexit would mean the need for new domestic legislation on state aid. It would however offer potential for greater flexibility in contentious areas such as alcohol pricing and free tuition in Scotland for EU students.

Mr Livingstone said negotiations might lead to the UK having to commit to retain principles which had driven an exit vote. “Biltaeral free trade might come at a price, which might include things like free movement of people.”

David Bell, professor of economics at Stirling University, said an exit vote would threaten the 15per cent of the EU’s research and development budget spent in the UK, could destabilise Ireland, and might require a redrawing of employment law.

Professor Bell said the EU had a lot to lose from withdrawal of the UK, which ran a budget deficit with the EU and was one of the major financial contributors. The UK could also, on current projections, overtake Germany as Europe’s biggest economy within 30 years. He noted that opinion polls around the EU now found a majority of citizens wanting to loosen, not strengthen, the grip of the centre.