Working Tax Credit

Hi,

I have only today discovered Working Tax Credits.

I am not currently in a position to claim them but wanted to know if I could claim for a previous tax year?.......

In the 2011-2012 tax year I only earned around £12,000. My understanding is that you need to be earning under £13,000 (This year) to be able to claim Working Tax Credit, the last tax year earnings limit may have differed?

I fit all the criteria to claim, over 25, worked over 30 hours a week etc.

I would be very grateful if anyone knows if I can claim for last years tax year.

Thanks.