SCOTLAND last year attracted its greatest annual number of foreign direct investment projects for 15 years, according to a survey that signals international companies have not been scared away by the independence debate.

Chancellor George Osborne has been among those who have claimed constitutional uncertainty is a cause for concern among some potential inward investors looking at Scotland.

But the latest annual "attractiveness" survey, published today by accountancy firm Ernst & Young, shows 76 foreign direct investments (FDI) into Scotland were announced last year, a jump of 49% on the 2011 figure of 51.

This is the greatest number of projects announced in any year since 1997, when Scotland attracted 88 foreign direct investments.

And Scotland's share of all FDI projects unveiled in the UK jumped by nearly 3.5 percentage points last year, to 10.9% from 7.5% in 2011, in what Ernst & Young describes as a "sparkling" performance.

Ernst & Young notes the only year on record in which Scotland attracted a greater proportion of UK projects was 2004, when it secured 11.4%.

It also observes that only London attracted more inward investment projects than Scotland last year, as was also the case in 2010.

Ernst & Young says of its latest attractiveness survey: "One issue that it identifies as having little or no effect on levels of FDI is the current debate surrounding Scotland's constitutional future, saying there is no sign of investors being deterred from coming to the country."

In the report, Ernst & Young says: "The possibility of independence and its potential knock-on impacts on areas such as corporate taxation appear to be having little effect on FDI decisions. There's certainly no sign of investors being deterred from coming to Scotland; if anything, the reverse appears to be true."

The number of jobs planned in Scotland through FDI projects unveiled last year was 4867. This was down 18% on the 2011 figure of 5926, but was nevertheless the second-highest in 12 years.

Ernst & Young said business services led the advance in foreign direct investment into Scotland last year, with the number of projects from this sector jumping to 15, from six in 2011. Among the projects unveiled last year was the creation of 150 jobs by the then Indian-owned HEROtsc at its call centre in Glasgow. This HEROtsc business, which was sold earlier this year by its Indian owner to Paris-headquartered Webhelp Group and is now known as Webhelp TSC, is run by David Turner.

Ernst & Young emphasises foreign direct investments unveiled for Scotland in 2012 were spread broadly in terms of sector and locations.

Manufacturing as a whole accounted for about 31% of these projects in Scotland in 2012,.

Although there were significant numbers of oil and gas and renewable energy-related investments –including Spanish group Gamesa's announcement of plans to create about 800 jobs at a proposed wind turbine manufacturing plant at the Port of Leith in Edinburgh – these did not dominate the overall figures in terms of the number of projects. The biotech sector was another important source of foreign direct investments into Scotland.

The US remained the biggest source of foreign direct investment into Scotland, accounting for 41% of the projects unveiled last year.

Ernst & Young notes that while Scotland was also successful in securing French, Norwegian and Swedish investment, it did not keep pace with the rest of the UK in attracting investment from emerging economies. It notes that Scotland attracted two projects from India, and one from China. There were none from central and South America, or from the Russian Federation, which were sources of foreign direct investment for other parts of the UK.

The 49% jump in foreign direct investment projects for Scotland in 2012 was way ahead of a 2.7% rise UK-wide. The UK attracted 697 such projects last year.

In the UK as a whole, the planned number of jobs from foreign direct investment projects unveiled in 2012 was 30,311, up 1.4% on 2011.

Scottish Finance Secretary John Swinney said of the Ernst & Young survey: "Scotland's success at securing inward investment is clear and, as this welcome report states, 'there is no sign of investors being deterred from coming to Scotland; if anything, the reverse appears to be true'."

Jim Bishop, Scotland senior partner at Ernst & Young, said: "As new markets open up and competition for FDI intensifies, securing investment will become more difficult for all countries, including Scotland.

"However, next year's referendum hasn't acted as a barrier to investment so far, although that may change as the discussion intensifies. What we can confidently say is Scotland's voice is being heard all the more clearly by investors as things stand."

Ernst & Young declares Scotland is "increasingly outperforming" most English regions in the race for foreign direct investment, and highlights the "pro-active efforts" of taxpayer-backed Scottish Development International and the Scottish Government.

International investors rank Scotland as the fourth-equal most attractive location among UK nations and regions in the latest Ernst & Young survey, up from eighth a year earlier.