To add on the last comment, you need to of worked 26 weeks out of the 66 weeks that are in your test period. Your test period is 66 weeks before the week the baby is due.
Even if you have worked for years before that it wont count. I nearly lossed out to my maternity allowance because i was two weeks off the 26 weeks period, luckly i found a months work so now im just waiting to hear back from them.
Even though you may send your claim off early i was told when i rang up they wont look at it until your due to get your money...Its a right pain!
Hope this has helped, i feel an expert over this subject seein as i ring them all the time !