UK maternity laws/rights. Do they hold my job?

I have a second interview for a new job today. Its better pay less travelling etc and i really want it.

Been at my current job 2 years. Love it but its really far away and not much money. Its hard to make ends meet. If i stay in this job would have to go back to work asap and put baby in nursery.

We're trying for a baby... due on period in a week. so may or may not be pregnant. Been trying 9 months.

My question is if i started this job financially how will that leave us? What am i entitled too etc? what with not being there long.

But also a friend has told me that being there under a year they may not keep a job open for me when i go off on maternity. This worries me.

But obviously i dont want to mention it in interview as i dont think i;d get the job if i did!!!

Its call centre work by the way, nothing strenious! So would be perfectly capable to do it pregnant or other wise.

I will read all information given before taking the job if it was offered...
Just hoping someone has some more info for me!