Strictly speaking, it's a person's job that becomes redundant - and the unfortunate job holder is the one to be let go.
If it's the case that you both had the same role but that you were the person "chosen" for redundancy, then you might have a case for unfair dismissal by virtue of your seniority. As the previous OP has said, you're entitled to know the rationale that was applied in deciding that YOUR job was the one to be made redundant.
I think many employers are using the current downturn to effect changes they wouldn't normally get away with.