If the account is in the child's name it will be tax free (just like an ISA) (unless the interest exceeds £100 a year in which case it counts a s parental income), so an ISA has no tax advantages. So it depends mainly on the rate of interest and whatever other factors are key to you
hi CC, we went for a child savings account with my bank for our little girl - i ddin't really fancy the idea of an isa, in case i needed to raid the savings at all before she has control of them, and with an isa you can't do that - as soon as the money hits the account, it's hers and she can't get it till 18