Jobs threatened at Jabil electronics plant in Livingston
Electronics firm Jabil has announced plans to close down its manufacturing operations in Livingston, with the loss of about 260 jobs.
The US-owned company said it expected to end manufacturing by the end of this year following a "phased run down".
Nearly 100 "support-based employees" will continue to work at the base.
Jabil said a strategic review had concluded there was "unsustainable" demand to support manufacturing at the West Lothian site.
It has launched a formal consultation process with employees.
Jabil said its plant in Ayr would not be "impacted" by the move.
The news comes less than two years after Jabil announced it was creating more than 200 jobs with a £12.5m expansion of the site.
The move was supported with a £450,000 grant from government agency Scottish Enterprise.
The Livingston plant, which is owned by US-based manufacturing services company Jabil Circuit, builds systems for firms developing emerging technologies in sectors such as energy generation and telecommunications.
In a statement, Jabil said: "Following a detailed strategic review of the Jabil Livingston site business plan and future loading requirements, we have concluded that there is unsustainable current and future demand to support the viability of manufacturing at the site.
"After careful consideration of all possible options, we are today announcing the commencement of a formal consultation process with our employees, with the intention of a phased run down of manufacturing at the site.
"It is anticipated that manufacturing will cease by the end of calendar year 2017."
It added: "This announcement is in no way a reflection of the hard work, dedication and loyalty of our Livingston-based employees.
"We are committed to supporting them throughout the consultation process and subsequent career search."
West Lothian Council said it would do all it could to help those affected by the proposed closure.
A spokesman said: "News that the plant is to close is extremely disappointing and our immediate thoughts are with those staff affected and their families.
"We will seek to meet with the Jabil's senior management and our partners as quickly as possible to discuss all and any alternatives to safeguard these jobs."
West Lothian suffered a major jobs blow earlier this month, when pharmaceutical giant Johnson & Johnson announced plans to close its surgical suture manufacturing plant in Livingston, threatening about 400 jobs.
Scottish government business minister Paul Wheelhouse said: "I am very disappointed to learn that Jabil is entering into consultation with staff on 260 possible redundancies at its Livingston site.
"I know this will be an anxious time for the company's employees and their families and a matter of concern to the communities of West Lothian in the context of the announcement of protected job losses of Ethicon as well."
He added: "Our focus at this stage is on engaging with the company to do everything we can to encourage them to maintain employment at the site."