On a constant currency basis, revenue was up 8.2%, chiefly due to the 8.6% decline in the US dollar against the pound sterling. Like-for-like revenues, excluding the impact of acquisitions and on a constant currency basis, were up 5.0%. On the same basis, gross margin was up 5.1%. Like-for-like revenues were up 5.3% in the first half of 2007 and up 4.8% in the second half, continuing the strong organic growth of 5.4% in 2006. Fourth quarter revenues were up 4.9%.
The relative weakness of the US dollar against the pound sterling has highlighted currency differences between those companies that report in US dollars and those that report in pounds sterling. So that comparisons can more easily be drawn, we have summarised in Our 2007 financial statements - Consolidated income statement the key income statement numbers, as if the Group had reported in US dollars in 2007. On this basis, revenues were up 13.6% to $12.4 billion, headline profits were up 16.5% to $1.865 billion and diluted headline earnings per share up 18.1% to 92.6¢.