Tax (VAT). Environmental groups argue that these, along with duty-free sales, are iniquitous tax concessions valued at £9 billion annually. Despite generating £6.9 billion in exports in 2004, representing 3 per cent of all UK exports and 7 per cent of the total export of services, the patronage in the UK of air transport services provided by overseas airlines resulted in a £3.3 billion balance of payments deficit attributable to the industry. Indirect economic contribution The government's response to the challenges of an increasingly global economy is to build a "strong, modern knowledge economy", and the 2006 OEF study concludes that the UK economy is "…set to become increasingly dependent on aviation as the structure of the economy evolves." The availability of air transport services is regarded as an important factor in facilitating business activities, with benefits being realised in sales and marketing activities, customer and supplier relationships, the ability to serve a wider market, access to emerging markets, and more efficient production. Within industry sectors that are likely to support the development of a knowledge based economy, such as pharmaceuticals, banking and finance, communication services, computer services etc., there is conflicting evidence about a correlation between growth in a sector and that sector's use of air travel, although survey results show that knowledge based services and high-tech manufacturing businesses are more dependent on air transport for sales than their more traditional economy counterparts. The most successful example of the country's economic evolution is the international financial services industry based in London. Within this sector aviation services are seen as critically important for both businesses and their clients, even in the era of video-conferencing. London's air transport services are widely regarded within the London business community surveyed by the OEF to provide a competitive advantage over the rest of Europe, and expansion of airport capacity in the South East has significant support. Whilst these economic contributions are not disputed by environmental groups, they are not considered as sufficient justification to support further growth in air transport services which would primarily service increased demand for leisure travel rather than a business travel market which is already well served. Transport links generally are regarded as an important factor which affects a company's decision on where to locate, and thus invest, although the latest survey shows quality of telecommunications moving above transport in importance. Survey evidence indicates that a quarter of companies regard