The company will move 1.5 million tonnes of biomanufacturing from India to Montrose in Angus.
On inspecting the two sites at Irvine and Montrose, Chief Executive Andrew Witty said: “To put it simply, we are looking for the highest quality with the most cost-effective process. I’m equally impressed by all the sites. A decision is expected in the first half of 2012.”
GSK already spends £160m on its Scottish manufacturing facilities, which produce 12 active pharmaceutical ingredients for 20 products.
The increased investment is part of an effort by GSK to re-establish its manufacturing in the UK and to increase its focus on products for emerging markets.
“A few years ago, if you had said you were moving manufacturing processes from India to Scotland, no one would have believed it,” Andrew Witty added.
“Payroll is not the issue. Actually, our payroll in Montrose is double the payroll in India. What has made the difference is the workforce and its extraordinary emphasis on efficiency. The Patent Box also helped.” (Find out more about the Patent Box.)
The Montrose plant will manufacture the chemical compound betamethasone, a potent steroid used in creams to relieve skin irritation and will increase its staff from 250 to 280.
The Irvine plant had laid off 200 workers in December, but Witty insisted this was all part of the company’s plan to “put the operation in a much stronger position”.