According to an internal memo, issued on May 29, jobs are being cut across a range of posts within the company.
Executives and project managers to IT specialists and operational support are all faced with the chop.
The global company, which has sites throughout the UK, was hoping to keep news of the job losses under wraps — but one disgruntled employee has shown the Mail material which discusses the plans.
It is not yet known how badly the Farnborough site — which employs about 1,000 — will be affected by the cuts.
The insider, who did not want to be named, says the strain is beginning to tell on workers waiting to find out who is safe and who isn't, and added: "The atmosphere is about as bad as it can get.
"Morale is very low. People have been off with stress-related illnesses, and that is at management level too.
"I don't care, personally, if my head is on the block or not but I know some of them really care, some of them are actually cracking up."
The source continued: "I think about the middle of July the staff will be told who is at risk and who is not. But we first heard about the redundancies at the beginning of May.
"People have been under stress for that amount of time and it's not on."
Staff who have accepted voluntary redundancy pack-ages are due to leave at the end of this week but more are expected to go in August.
Employees are to be assessed against a set of criteria including attitude, skills, experience and potential, resulting in a score reflecting how useful they are to the company.
Guidance has been set out for managers to use should a "tie-breaker" situation arise where one or more employees score the same total.
Under this guidance a "last in, first out" rule is one of the principles applied.
Despite the pressure, our contact said that colleagues are resigned to the situation.
"I think it's gone too far for people to try and outdo each other now because the decisions are going to be made on this scoring which includes previous reports and line managers' comments and all that, so it's too late to do anything about it.
"Some people want to go and the reason they want to go is because they are so fed up with the company and the top management and the way they're treated and spoken to."
We contacted IBM's head office to find out how much the Farnborough offices would be affected.
A spokesman told us yesterday: "We announced our voluntary redundancy packages in the last month.
"We have 25,000 employees in the UK and it will be a very small number of those that will be made redundant.
"I don't think we will notice a great impact on any particular centre."
Employees learnt in May that the company was planning to "streamline" the company after "disappointing business results" called for a far-reaching set of initiatives for the company's recovery.
In a memo sent on June 24, the redundancy programme is outlined.
Staff who have accepted voluntary packages are due to leave on July 5.
Employees will be notified around mid-July if their job is at risk or safe.
Any further redundancies will take effect in mid-August.