The 303-strong workforce at the Cobden Street plant were told of the new round of redundancies on Tuesday, however the decision over which jobs are to be axed will not be taken until a staff consultation process is completed over the next few days - meaning employees face a nervous wait to discover if their position is safe.

GSK had also previously confirmed that 69 temporary staff were to leave the Montrose factory by the end of 2008, meaning a total of 124 jobs are set to be lost within a year.

A spokesperson for the pharmaceutical giant said: "In response to falling demand for several products made at Montrose, a month-long review of site operations was undertaken.

"It concluded that the workforce would need to reduce to around 250 by the middle of 2009 for the site to remain sustainable in an increasingly competitive environment.

"Staff at the site have been informed of proposals, which are now subject to consultation with employees and their representatives, to reorganize and restructure activities at the Montrose site.

"Under the proposals, Montrose would retain its position in the GSK network as a global supplier and strategic back-up site for active pharmaceutical ingredients."

The latest round of job cuts follows an earlier announcement by GSK that it was to undergo a £1.5billion global restructuring programme.

The town's four local councillors were united in dismay at the news and they all said they hoped the redundancies didn't hint at a bleak future for the factory.

Councillor Paul Valentine said: "I used to work there and have a lot of friends there – it's very concerning.

"There may be people who take voluntary redundancy but I don't imagine there will be 55. It's very sad to see the number of people who are potentially going to be losing their jobs.

"They have put a lot of money into the economy over the years and if it shuts down completely then it will be a massive loss for Montrose and Angus."

Councillor David May said: "My immediate concern is the loss of income for the families - the husbands, wives, sons and daughters.

"I have asked the head of economic development to arrange a meeting with representatives from GSK to see what their plans are, which should take place quite soon."

Councillor Mark Salmond said: "I am obviously very disappointed that GSK will be reducing their workforce by 55.

"I am though very reassured that GSK see a future for the plant in the GSK network as a global supplier and strategic back-up site for active pharmaceutical ingredients.

"In the past they have played a major role in the community of Montrose and I hope they will continue to do so in the foreseeable future."

SNP councillor Sandy West said: "If you look back a bit, the town was quite jubilant (at the news] that they were not closing, then straight away they took on a large number of staff.

"There have been various announcements that they are shedding staff and this is just the latest episode.

"I'm concerned - it's as if they don't know what they're doing. They take staff on and then they let them go.

"I am reassured that Andrew Welsh is speaking to GSK at the London end and they have assured him closure is not an option."