Outsourcing giant Serco has reconfirmed the update issued last month noting that it expects strong organic revenue growth and progress towards its 2012 margin guidance in the year ending 31 December.The group, which provides management and consulting expertise to the public sector, remains confident of its full year results, which it says are underpinned by strong global demand for its services.The statement issued Thursday says that this demand drives "significant opportunities for Serco in both existing and new markets, and by our operational and financial performance."The company reiterated previous guidance of an increase in revenue to around £5bn and a rise in adjusted operating profit margin to about 6.3% by the end of 2012.Serco runs a wide range of public sector operations including prisons and the Docklands Light Railway in London.