MAJOR cost overruns have hit all of the Olympic Games, new research by Oxford University academics has found.

Bent Flyvbjerg and Allison Stewart of the Saïd Business School found governments overspent on the games by 156 per cent on average.

The 'gold medal' for costs went to Sochi in 2014, they said, which cost $16.3bn (£12.4bn) more than the planned $5.6bn.

Meanwhile the Barcelona 1992 games overspent by $7bn (£5.3bn) and London 2012 by $6.5bn (£4.9bn).

Rio 2016, due to run from August 5 to 21, was set to cost $1.6bn (£1.2bn) more than planned.

The smallest overspend was on the Beijing 2008 games in China, where authorities overspent by $100m.

By comparison, the researchers said the average overspends on other major government schemes were 20 per cent for roads, 34 per cent for large bridges and tunnels and 45 per cent for rail projects.

Professor Fintzen said: "With 100 per cent consistency in overspending, the Olympics are in a class of their own.

"This is why they will always be publicly funded. In projects involving private-sector investment, you can’t afford such overruns, but these projects can also quickly get into trouble if effective cost-control management is not in place."