Glass manufacturer Pilkington is to cut production at a UK factory under plans to axe 3,500 jobs worldwide.

Unions were trying to establish how many jobs will be lost in this country as a result of the move by Japanese owner Nippon Sheet Glass.

The company, which employs around 3,000 people in the UK, said in a statement: "The group is taking action to reduce capacity and output to match the requirements of its customers. This will include the mothballing of one of the group's float lines in the UK.

"This follows the announcement on December 15 2011 of the group's decision to delay the construction of a solar energy line in Vietnam. Further actions will be announced once due process has been followed with employees and unions affected."

The company blamed worsening conditions in many of the group's core markets, particularly in Europe, citing weak building product markets and a slowdown in solar energy glass.

The GMB union said it understood 150 jobs will be lost at Pilkington's site in St Helens.

Charlie Leonard, GMB senior organiser, said: "This has come as such a shock.

"Many of the 150 jobs expected to go at St Helens will be young workers who have been taken on recently following a short-lived upsurge in demand. GMB is working to reduce the number of job losses and the impact on the local community."