The US government failed to prepare adequate procurement and contracting systems before its 2003 invasion of Iraq, a predicament that has severely hampered the $20bn (€16bn, £11bn) reconstruction effort, according to a report released to Congress on Wednesday.

Stuart Bowen, the special inspector-general for Iraq reconstruction, said the US needed to overhaul and simplify its current contracting and procurement procedures for “universal use” in future post-conflict situations.