Biggest Budget Overruns in History

The most famous budget overrun in history. Architect Jørn Utzon won the competition with an incomplete design, meaning costs were estimated before engineering was complete. The iconic shells required entirely new construction methods to be invented. Utzon resigned in 1966 amid political interference, and the interior was finished by others — to a compromised design.

The most expensive weapons program in history — and one of the biggest budget overruns. The F-35 was conceived as an affordable multi-role fighter but became a $400B+ programme plagued by concurrent development and production (building planes while still designing them), software complexity (8 million lines of code), and a single prime contractor (Lockheed Martin) with limited competition.

Boeing's revolutionary carbon-fibre aircraft overran massively due to an unprecedented outsourcing strategy. Boeing outsourced 70% of design and manufacturing to global partners to reduce cost — but the partners couldn't integrate, causing two-and-a-half years of delays. Battery fires after launch caused a global fleet grounding. Total programme overrun exceeded $12B.

The launch of the US Affordable Care Act's health insurance marketplace was a catastrophe. The site crashed on day one, unable to handle load. A post-mortem revealed 55 contractors working on the project with no single point of accountability, government procurement rules preventing agile development, and political pressures preventing realistic launch date reconsideration.

The UK's biggest infrastructure project became its biggest infrastructure embarrassment. Costs tripled as the route was planned through dense urban areas, then Phase 2 (Birmingham to Manchester/Leeds) was cancelled entirely in 2023 after £2.7B was spent on it. Complex geology, utility diversions, community opposition, and inflation all contributed — but the fundamental failure was political: a project approved before engineering was mature.

Planned to open in 2011, Berlin's new international airport finally opened in 2020 — nine years late. Faulty fire protection system design required complete rewiring (640km of cable). A governance structure with three owners (city-states of Berlin and Brandenburg plus federal government) made decisions nearly impossible. Successive airport CEOs were fired. The opening was postponed five times.

The world's largest civil IT project at the time was abandoned after 8 years and £12.7B spent, having delivered almost nothing. Local NHS trusts rejected the centrally-designed software. Clinical workflows were ignored. The governance structure meant no one could make decisions, and the prime contractors (including Accenture and Fujitsu) walked away or were paid off.