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* Q1 organic revenue growth 0.3 pct vs year-ago 7 pct
* Overall group revenue up 3.6 pct on constant currencies
* Sees better growth and profitability in second half
* Shares down as much as 7pct (Recasts with drop in recenue growth, adds shares, analystcomment)
By Li-mei Hoang
LONDON, May 16 (Reuters) - British testing firm IntertekGroup Plc posted a sharp decline in underlying revenuegrowth in the first quarter, blaming variable market conditionswhich it said had affected activity in its energy infrastructuredivision.
Shares in the company, which tests everything from oil tochildren's toys to check they comply with regulatory standards,dropped as much as 7.2 percent on Friday to become the biggestloser in the FTSE 100 index of blue chip stocks.
The company said on Friday revenue growth had dropped to 0.3percent on an "organic" basis, excluding the effects ofacquisitions, from 7 percent in the same period a year ago.
It said, however, it had seen good growth in its keyproduct-related business, forecasting better growth andprofitability in the second half of 2014 on the back ofimproving market conditions.
Overall group revenue growth reached 3.6 percent on aconstant currency basis, the company said, adding that itsoperating margin had improved slightly as expected as itbenefited from restructuring activities.
Mike van Dulken, head of research at brokerage AccendoMarkets, noted the stock had been hard hit by the company'sconfirmation that tough conditions had continued into the firstfour months of the year.
"With revenues barely growing organically and hindered by astrong (pound), cost control will be paramount with an outlookciting variable growth in key businesses and weak demand inothers," van Dulken added.
At 0816 GMT, shares in Intertek were down 5.1 percent to2,930 pence. They fell as low as 2869p, their lowest since earlyMarch. (Editing by Brenda Goh and David Holmes)
