If you are collecting retirement benefits can you also collect unemployment benefits?

Theoretically yes, the government will take what you are getting in pension away from the amount they think a person needs to live on per week and if there is a difference they will make this up as the unemployment payment. If your weekly pension income is more than the amount, you will not get any unemployment payment but you will be credited with your national insurance stamp each week (you will need 30 years of stamps to get a full state pension at state retirement age). You will also be entitled to the other unemployment concessions.