This is the reality as I've just been through this.
I got the vibe that redundancy was around the corner and Post Office Lifestyle was the best insurance at the time (£40 per month, with £1000 per month pay out for 12 months).
I took out the policy and it said in the small print that you must have been in employment for 60 days from the start date of the policy.
Fortunately I qualified although only just!
There is a 1 month delay before payment but they did honour the policy.
The pain is that when you sign on (usually every 2 weeks) you must make a separate appointment to get your ABI-1 forms filled out and signed for at the job centre, however, you don't send the form off until you've done this twice as it's a monthly payment – if you get this wrong it's a real hassle. They'll also want to see evidence of you trying to get work too.
I had £500 for my mortgage and £1000 protection (for 12 months) plus Job Seekers Allowance (only for 6 months) in the end which was really helpful.
So my advice is go for the Post Office option ASAP (I think it's now £60 per month) and hope that you're not made redundant before the set qualifying time.
Any questions please contact me.