The short answer is that I won't be able to manage.
Baby is due February, all my savings went on getting pregnant in the first place, but to be honest, if I'd waited for the more cost effective route of marrying and saving, I would have run the risk of never having a kid, so I totally don't regret not saving.
On the practical side of things I have got a modest(ish) loan from the bank. This has been put in an ISA, so it's separate from my current account, but still easily accessible. I've set aside enough money to cover my mortgage during the second half of my maternity leave - 7 1/2 months off thanks to a healthy padding of annual leave at the beginning and end; I get 18 weeks at 90% of pay; thanks to work, before down to £139p/w minus tax where the loan money will kick in to cover things. I've also set enough aside to cover the monthly loan repayments until I'm working again. It'll probably be quite tight at times, but it'll be doable. If I ever have a week when I have no money for food or fuel I can either dip into the last dregs of the loan (to be kept for emergencies) or can walk round to nearby family for a meal.
The loan isn't ideal, but it's enabled me to get a naice pram, and to not have to worry about all the other baby-related purchases; I'm not angsting over how to afford maternity jeans, baby clothes, bottles, nappies, etc. It's given me the chance to enjoy pregnancy, which is great as unless things change in the next 5 or so years, this is likely to be my only child.
Not sure if you qualify for Child Tax Credits. Annoyingly I don't - I get paid too much to qualify, despite the fact that a: I'll not be getting that pay during my Mat Leave, and b: I live in an expensive part of the country, and so a large proportion of my income goes straight out to the mortgage. But that's my fault for not picking somewhere cheaper to live.