An increase of 25% in the cost of a large high-tech project like the LHC is not unusual, according to Roger Cashmore, CERN's director for collider programmes. But such rises are usually factored into the original price. No such allowance was made in the case of the LHC. "In the US you would take the base price and add 40%," says Cashmore. "So these overruns are what prudent people would expect. I'm afraid the chickens are coming home to roost."

It is not clear at this stage how the extra costs - which came to light at a meeting of CERN's finance committee last week - will be met. Cashmore says that there are no technical problems with the LHC and that CERN still intends to collide the machine's first protons in April 2006, although he admits that problems with civil engineering could delay this. By sticking to its schedule, CERN will therefore have to enlarge its annual SFr1bn budget by a few per cent over the next five to ten years, or add to the loans that it originally took out to pay for part of the project.

The issue will be discussed at a meeting of CERN's finance committee in November and then at a council meeting of the member states the following month. Cashmore says that by this time there will have to be "very clear statements" about the budget.