A decision is finally expected on whether to move hundreds of government science jobs out of Wiltshire to Essex.
The UK Health Security Agency at Porton Down researches how to tackle the world's most infectious diseases, and prepare the UK for future pandemics.
Over the last 15 years plans have been worked up to relocate its 900 workers to new facilities in Harlow, but the estimated costs have spiralled – ministers expect a final decision in Wednesday's government spending review.
The MP covering Porton Down – Conservative John Glen – said: "It's taken 10 years to still be in doubt whether this should still happen and the costs have gone up six-fold."
The National Audit Office reported the cost of the whole project is estimated to be £3.2bn, a figure more than 500% higher than the initial forecast of £530m.
When it was officially announced in 2015 that the labs would move to Harlow, Essex, the MP there at the time said he was pleased and it would "bring thousands of jobs".
Speaking to the BBC this week, Mr Glen said the new build would be "dressed up" as a world-class hub.
"But Porton Down already is world-class," he said.
"We've already got the world's best scientists doing amazing collaborative work."