FTSE-250 building firm Carillion has issued a mixed third quarter update saying performance is in line with previous guidance.The good news was that it continues "to expect to deliver improvements in operating profit and total operating margin" for the full year ending December 31st 2012.The bad news is that full year revenues will be down on 2011, due to it reducing its UK construction activities to cope with lower activity. Net financial expenses, as flagged at its interims will increase due to higher interest charges.Its pipeline of contract opportunities remains strong, particularly in the Middle East, and has completed the sale of further equity investments in Public Private Partnership projects, generating £15.4 cash.Year-end net debt, at £115m, is expected to be around the same level as at the half year. CM