The internet accounts for 25% of all advertising in the UK

"UK online advertising has bucked the recession with strong growth of 12.8% on a like-for-like basis in 2010 to reach a new milestone of £4,097 million, according to the bi-annual advertising spend study from the Internet Advertising Bureau (IAB) and PwC.
With total UK advertising spend in 2010 valued at £16.6 billion, this takes the internet’s market share to a record high of 25% (23% in 2009), meaning that £1 in every £4 invested by advertisers is spent online.
These findings demonstrate that, despite the recession, online advertising is in rude health. Significantly, marketers are increasingly using online channels to drive their brand building campaigns. Consumer goods and retail advertisers increased their investment in online to become two of the top four big spenders in display, capitalising on the medium’s core strengths of reach and engagement as well as accountability.
In 2010 the biggest gain was display advertising, thanks to a nearly 200% surge in display advertising in a social media environment (on a like-for-like basis)* and 91% year-on-year (absolute growth) in video formats. Expenditure on pre-, mid- and post-roll video advertising nearly doubled to £54 million (£28 million in 2009). Overall display grew by more than a quarter (27.5%) on a like-for-like basis to a new high of £945.1 million, representing 23% of total online spend (up from 20% in 2009).
Consumer goods manufacturers became a top three display spender in the first half of 2010 with 12% share, jumping to 13% in the second half. The top spender in online display is finance with 15.2% share, indicating that as the economy recovers, finance brands are seeing their marketing budgets re-emerge. Finance market share has overtaken entertainment and media, which has dipped slightly to a 14% market share.
Paid-search continues to perform strongly with growth of 8% year-on-year on a like-for-like basis to £2,346 million, representing 57% of total online spend (61% in 2009).
Despite pressure on the housing, recruitment and automotive markets, online classified advertising bounced back in 2010 recording 9.7% growth on a like-for-like basis to £751 million – a share of 18% (19% in 2009).
Mobile advertising has experienced a staggering 116% year on year growth (on a like for like basis), up from 32% in 2009. Advertisers spent £83 million on mobile advertising in 2010, led by the entertainment and media sector, but with encouraging growth from finance, telecoms and consumer goods advertising."
Source:  Data from IAB / PwC, reported on the IAB UK website, 29th March 2011