It is the focus of Scotland's global profile and arguably its most crucial industry, but nobody really knows what impact Brexit will have on tourism.

Ben Nevis, Glencoe, Edinburgh Castle, the Glenmorangie distillery and the old course at St Andrews will be still here. But will there be as many visitors with as much money?

These are important questions. Spending by tourists in Scotland generates around £12 billion of economic activity in the wider Scottish supply chain. It contributes around £6 billion to Scottish GDP, which represents about 5 per cent of the total, and secures employment for over 210,000 people.

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Market researcher Euromonitor has predicted 2.3 million fewer visitors to the UK over the five years up to 2020 following the Brexit vote.

However the fall in Sterling after the referendum, immediately made the UK a more attractive destination for international visitors. There also seemed to be an early rise in this planning a 'staycation' rather than going abroad.

But the Scottish Tourism Alliance (STA) is reserving judgement.

The umbrella group representing more than 25O bodies connected to tourism and the leading voice for the sector, says there is conflicting evidence.

Marc Crothall, STA Chief Executive said "Hotel and holiday deals website Travelzoo reported a spike in searches to the UK from the US and China immediately after the vote. Searches for flights to the UK went up by an average of 60% post-Brexit announcement according to the company.

"However, a question mark exists over business travel to the UK and Scotland. According to PwC (multinational professional services network headquartered in London), hotels need almost twice as many new leisure visitors to make up for business travellers who have cancelled. With the political and economic uncertainty, many businesses are unfortunately putting plans on hold.

Read more: Beyond Brexit - Scottish passport plan could allow Scots to keep working and living in Europe

"Holidays to Scotland may be cheaper due to the fall in the pound, which could prove to boost for the tourism and leisure industry."

In the longer term nobody knew how the UK's move to exit Europe would affect Scottish tourism. But he said it was probably safe to say that any short-term gain in relation to a weaker currency would be significantly offset by the impact of changes to access to European markets.

He feared uncertainty in the rate of Sterling could also create problems for inbound tour operators resulting in delays in securing contracts with hotels, carriers and ground agents. Changes to tariffs on European produce, in particular food and drink, could increase prices, reducing our competitiveness further. "Out of 141 countries, the UK ranks 140 on price competitiveness," he said.

Meanwhile the renegotiation of European air access agreements and any possible changes in the UK’s status as a European and international air hub could lead to higher air-fares and fewer flights within Europe.

But the Scottish industry definitely had fears over the Brexit impact on future staffing, Mr Crothall said.

"One of the critical issues for industry is the potential changes to the free movement of people which will directly affect the sector’s ability to attract, employ and retain overseas staff, both seasonal and permanent. EU migrant workers are a vital part of the tourism sector and we welcome and value their contribution to what is the most important industry in Scotland."

Read more: Beyond Brexit - Scottish passport plan could allow Scots to keep working and living in Europe

Scotland’s tourism industry had a huge skills shortage and more than ever a real commitment was needed from government to address the issue.

"There is no doubt that this is a major concern for tourism businesses, particularly within the hospitality sector. On the flip side, this apparent challenge also represents a huge opportunity to encourage more young Scots into the sector.

What we do know for sure is that as Scotland’s most important industry, tourism is here to stay. Tourism is not a large corporate that can be moved to a ‘friendlier’ commercial environment. It’s here, all around us. It’s our history, our heritage and our future. People want to visit our country. We need to make it as competitive, and attractive for them to do so."

He said strong leadership was needed in these uncertain times.

One B&B operator near Fort William said the Brexit vote wasn't helping her business: "I had a Spanish couple who were really heartbroken at the referendum. They just couldn't understand why British people wanted to cut their ties to Europe. It was genuine disbelief. But I couldn't explain to them, because I still don't understand it myself."