A nanny is the most deluxe form of childcare for working families, but the quality of individual nannies is as variable as for any other form of childcare so the usual rules of choosing childcare apply - do your homework and trust your instincts.
What attracts parents to this form of childcare is that a nanny provides one-to-one care for your baby or child in your own home.
You don't have to struggle to get you and your baby out of the house in the morning and there's significant flexibility about their working hours, provided you're clear about what you require when you recruit.
A nanny can be 'live-in' or 'live-out/daily' and, of course, if you need a live-in nanny, you will need sufficient space - at least a spare room and, ideally, a separate bathroom, too.
Unlike a childminder, a nanny will be dedicated to looking after your child, so there will be no nursery or school-runs for other children (unless they are your own). Other bonuses of having a nanny are that you're the boss when it comes to your baby's food, routines and activities, and most nannies will do bits and bobs around the house - preparing food, washing baby clothes and clearing up toys and baby clobber.
"A nanny you love is an absolute blessing and worth every penny." Harrietthespy
A nanny will also look after your baby when he or she is poorly - this is pretty much the only form of childcare where this is an option.
But (there had to be a 'but' in this whole Mary Poppins scenario) the big downside is cost. Employing a nanny is likely to be an expensive childcare option unless you have two or more children, or do a nanny share.
Additional things to consider before you choose a nanny are that a nanny is in sole charge of your child when you're not around and this means she isn't supervised in the way a nursery worker is.
Regulation of nannies is lower than that for nurseries or childminders. Although some nannies are Ofsted-ed and you can ask for a CRB check. A mediocre nanny may spend all her time drinking coffee with other nannies and sending text messages rather than doing the things you have asked her to do.
Your responsibilities as an employer
Professional, qualified childcare
Looks after your child in your own home
No nursery-run (unlike childminder)
One person to bond with child – will become 'part of the family'
You're in charge of what your child eats
Help with child-related household tasks
May accompany family on holidays
You're dependent on one person for childcare (will need cover for sickness/holiday)
You'll need to be an 'employer' and need to learn about paying tax/National Insurance (although companies can do this for you)
Can be expensive to hire (advertising/agency fees)
A 'live-in' nanny will need space - bedroom/ bathroom etc
If you're already quailing inwardly at the logistics of going back to work, remember that, unlike any other form of childcare, if you hire a nanny you are her (or his) employer.
And this means shouldering the responsibility and admin it entails: recruitment and retention, and the practicalities of paying a salary (tax, NI, possibility of maternity leave, redundancy pay etc).
There are special 'nanny payroll' companies that can help you with the practical side of this, or you can throw yourself on the mercy of your local tax office and they can help you set up your own payment system.
One Mumsnetter warns: "There's a simplified payment scheme, which even I as a maths illiterate could manage, but once my nanny started working more than a couple of days a week, she earned too much to qualify for this and then I struggled. But the tax office folks were remarkably helpful."
Recruitment can be tricky - not just the anguish of deliberating over candidates to find 'the one' but also the costs involved in advertising or using agencies.
And you're dependent for all your childcare on one person, so if your nanny is ill or on holiday you'll need to find alternative childcare.
As one veteran nanny-employer warns: "One year I used my entire annual leave covering the nanny's sick days/ holidays. You can't legislate for illness, but it is worth checking with the nanny's referees how much time they take off for illness, and make sure you say when hiring that they either have to take holidays when you do, or give you heaps of notice so you can make alternative arrangements."
And, last but not least, you may have to deal with your own jealousy that someone else is getting to spend significant amounts of time with your baby (but this can be just as true with a childminder or, indeed, a keyworker at a nursery).