Independence for Scotland could reduce the opportunity for Scottish HR professionals to move talent between countries, according to a top recruitment expert.

Charles Macleod, director of global sourcing at PwC and a Scot based in London, told the CIPD's 2012 Scottish HR Conference in Dunblane that tougher restrictions on immigration in the UK and elsewhere, in combination with independence, could hit talent mobility.

"If Scotland becomes independent, the whole talent mobility thing could become very difficult," he told the conference on Friday.

Working out migration arrangements with other countries, he said, "could be very interesting for you".

The SNP majority government in the Scottish parliament intends to stage a referendum on independence in autumn 2014.

Macleod said talent management was now a top priority for global companies. According to PwC's recently-published Annual CEO Survey 2012, while 47 per cent of chief executives globally were "very confident about growing their businesses" over the next three years, only 30 per cent "were confident they would have the talent needed to do it".

Recruiting and retaining "high potential middle managers" was the greatest concern for chief executives everywhere – and also for PwC itself, said Macleod.

PwC has an annual global turnover of $30 billion, and 175,000 employees in 154 countries. It conducts 1,000 recruitment interviews every working day, "and while I'm speaking to you, 10 more people will join PwC around the world," he said.

One sign of the increasing competition for good middle managers is an increase in counter-offers from existing employers when staff hand in their notice to go to new jobs. "There's a huge amount of buying back going on now," said Macleod, and PwC has responded by investing in a programme to integrate new recruits swiftly.

Last year, for the first time, to strengthen retention and development, the firm also graded all its relevant people with an assessment of their future high potential.

"There was a highly-charged debate around the world about rating people in this way," reported Macleod. "I hope the first year of it will prove to have been the most difficult."

He revealed that 15 per cent of PwC's new hires globally are people who previously worked for the firm and return after a number of years. He himself had come back to PwC after 10 years. This sort of return rate is only possible, he said, "when people leave gracefully and with a good impression".

Macleod said that the proportion of recruits identified and recruited by PwC itself was increasing. "I got tired of sitting in rooms giving search firms lists of people we wanted them to approach," he said. "About 25 per cent of new starts now are people we find ourselves."