We may never forget the horror of 11 September but, nearly four years on, for the UK tourism industry at least, its impact has finally started to fade, even if the shadow of future shocks still looms large.
Last year saw 27.5 million overseas tourists come to the UK, according to national tourist board VisitBritain, an 11% increase on 2003 and the highest since the previous record set in 1998.
These visitors spent some £12.8b, up 8% on 2003 and equal to 2000. About half of this spending went on accommodation and eating out, estimates VisitBritain.
The British Hospitality Association has estimated that the UK tourism industry was worth £75.9b in 2003, calculating it as a combination of spending on fares and day trips, spending by overseas visitors and the value of overnight stays.
The overall volume and value of inbound tourism is forecast to grow at an average annual rate of 3% over the next five years, suggests Visit Britain.
"The tourism market is obviously subject to shocks, but that aside the general direction has been upwards since 11 September. More people are staying in hotels and they are spending at higher rates," says Marvin Rust, a partner at consultancy Deloitte.
"The general slowdown in the world GDP and the rising price of oil are likely to have an impact," says Rust. "London still has some way to go to get back to pre-11 September levels, although the UK regions are just about there - but that is before taking into account the effect of inflation," he adds.
New markets - such as China, Russia and eastern Europe - are coming to the UK in ever greater numbers. The agreement in January between China and Britain to allow greater numbers of visitors to come to the UK is a case in point.
Key markets to look out for in the future, argues VisitBritain, include Russia, South Korea, the Czech Republic, Greece, Hungary, Malaysia and Thailand.
The organisation is estimating that by 2010 there will be at least 200,000 visitors from China each year, rising to 500,000 a year by 2020 - and they are unlikely to confine themselves to traditional Chinese restaurants.
Similarly, many traditional markets, such as Germany and France, are seeing their populations age rapidly, so there is a strong likelihood that there will be an increasing proportion of older, more discerning but at the same time higher spending, diners and tourists arriving.
But, commentators argue, in terms of spending, these new arrivals do not compare with the big spending Americans and Japanese, whose numbers have still failed to return as much as the industry would like post 11 September.
Irrespective of the effect of 11 September, the number of tourism arrivals has doubled since 1980, argues Malcolm Preston, travel sector leader at PricewaterhouseCoopers.
In that time, the industry has seen the rise of the "DIY traveller", although they do not always spend as much as package tourists, online booking has become much the norm.
According to consultancy Keynote, a significant trend since 2000 has been for the industry to become more cost-conscious and profit-orientated, with the philosophy of "pile 'em high, sell 'em cheap" gradually being eroded - a trend hotels and restaurants are having to respond to.
For hotels, the key battleground has been in understanding what the increasingly disparate groups of tourists want, and winning the "battle for the hearts, minds and wallets" of the hotel customer, argues Preston.
The growth of the budget airlines has also had a significant knock-on effect, not only enticing UK travellers to new destinations but also opening up new markets for the UK, particularly from within Europe.
"As flights become more commoditised, the hotel will begin to emerge as the driver behind the customers' choices," Preston argues.
The rise of boutique hotels, which often act as a destination in their own right, is a case in point, he suggests.
Business travel, after the travails of 11 September, is once again performing strongly - with the budget airlines again playing a major part - and helping to fuel growth in the hospitality sector.
London winning the 2012 Olympics would inevitably be a huge boost for the capital, in terms of tourism, hospitality and infrastructure development, says Rust.
"It would really promote London as a global tourist destination and it would undoubtedly help the performance of the capital," he adds.
Because there is not that much scope for new infrastructure - hotels, arenas and so on - London would be less likely to suffer a post-Olympics hospitality hangover, he suggests.
Quality is likely to remain an issue going forward, predicts Rust. While in the hotel sector, in particular, the percentage of branded hotels - where quality is more likely to be more consistent - is higher than in Europe, there are still a lot of "old, tired, three-star assets" that can put off tourists.
The need to raise rates on the back of improved occupancy levels is also likely to continue to be an issue.
While London is unlikely ever to be knocked off its pedestal as the hub of the UK tourist trade, other regional centres and areas are set to continue to make headway. Manchester and Cardiff have both been doing well of late - with Cardiff in particular riding on the back of the success of its Millennium Stadium and, latterly, the Welsh rugby team.
"The sector, as we have seen since 11 September, is a resilient one, what with wars on terror, Sars, foot-and-mouth, even the possibility of bird flu," says Rust.
"The outlook going forward is positive, barring shocks, which are normally out of our control anyway," he adds.