GroupM, the media buying arm of WPP, has forecast the highest UK advertising spend since the economic crash and subsequent financial crisis of 2008 in their report 'This Year, Next Year UK'.

Predicting a market worth £13.9bn at the end of 2013, GroupM has more than doubled its growth projection - from 3.3% six months ago, to 7%. The driving force is the exponential growth of digital; an estimate of £7bn representing almost 50% of total UK ad spend in 2014. Online advertising currently accounts for approximately 44.2%, or £6.2bn.

Spending was at a low of £11.3bn in 2009 post Lehman-bros, and the recovery has been arduous. But the spring of digital has propelled growth into a state of anticipation.

GroupM futures director Adam Smith described the recovery as "spectacular, but not a phenomenon".

"UK annual GDP is likely to have risen 9% in cash terms since 2008, and annual advertising the same. The question is whether advertisers sustain their optimism that UK households are feeling richer, and might actually get richer, between now and the election expected in spring 2015.

"UK paid search has doubled in size since 2008 in cash terms and as a share of all UK marketing investment. Smartphones, tablets and e-commerce sustain this momentum. We think mobile (including tablets) will furnish 70% of paid search investment growth this year and all of it next year."