Product tester Intertek has made good start to the first four months of the year, boosted by the weakness of the pound.Total revenue for the first four months of 2009 increased by 42% at actual exchange rates. This comprised 7% organic revenue growth at constant exchange rates; 5% revenue growth from acquisitions made in 2008 and 2009; and 30% positive exchange rate movements. The group continues to benefit from favourable exchange rates when translating foreign currency revenues into sterling, in particular the US dollar, HK dollar, and Chinese renminbi."Our key business drivers remain robust and are expected to continue to produce good organic revenue growth throughout the year," chief executive Wolfhart Hauser said, adding he expects to keep margins stable.. The key growth drivers behind Intertek's business model remain robust as the business is only partially dependent on volumes of global trade. These drivers include: