Public sector maternity pay is quite varied here. I work in local government and the national agreement is I think still about 14 weeks maternity leave with pay above SMP. My employer's scheme is much better if you've been there long enough, there are 3 levels of maternity pay with the best being for women who've been there for at least a year. I had 16 weeks full pay and then chose 24 weeks half pay (the choice was that or 12 weeks full pay).
However, my baby was due the month that SMP changed (April 2007), and I only found out 2 days before I went that I could have had 28 weeks (16 + 12) full pay and then had 11 weeks SMP. Whereas SMP was included in my 16 weeks full plus 24 half - I believe that I might have been better off taking 6 months full pay.
There's another caveat for us - we have to return for 6 months afterwards or repay most of our money - one of my colleagues who has a daughter who will be 3 this August and twins born in April 2007 is doing just that and then resigning as she doesn't want to pay back her maternity pay, but has nothing left of her wages after paying childcare.
I believe adopters are also entitled to quite good benefits on terms similar to adopters under my employer's scheme.
All that said, the better schemes weren't just handed out as a gift to public sector workers. Most of them were originally won in workplaces with high levels of unionisation, although those levels have dwindled a little now. Union members fought for them.
I work in a legal department, the second council legal dept I've worked in, and I think some of my lawyer colleagues especially earn significantly less than they could in the private sector but have taken the trade off for maternity leave/flexible working schemes. Interestingly, while they don't take maternity leave a lot of men in our section have made good use of the flexible working policies too.