"It's regrettable that Carillion has not been able to find suitable financing options with its lenders, but tax payers cannot be expected to bailout a private sector company. Since the profit warnings were first issued in July the government has been closely monitoring the situation ... we remained hopeful that a solution could be found while putting robust contingency plans in place, " he told reporters.

"Our primary responsibility as always (was) being able to keep our essential public services running safely."

(Reporting Elizabeth Piper, editing by William James)