Faye, yes it is possible for a child in the UK to be adopted without their parents' permission, although the process is a very complex, long and drawn out one - hence the criticisms of the process where children are left waiting for permanence for months or years before the matter is resolved. Basically there are two ways a child can be placed for adoption; either with the parents consent or alternatively if the child is on a Full Care Order granted by the Court under the Children Act 1989. This applies in England and Wales; the law in Scotland is different (but from my limited knowledge, more family-friendly). The grounds for granting a Care Order are that the child is suffering or is at risk of suffering significant harm, and the onus is on the Local Authority to prove this 'on the balance of probabilities'. As you can imagine this can take a long time while evidence is gathered, assessments are carried out, reports are filed from Social Workers and expert witnesses, and Court hearings are scheduled. The Court will also appoint a 'Guardian ad Litem' (an independent Social Worker) whose role is to provide an independent assessment of the child' s best interests. The child also has independent legal representation. The child is usually in foster care while this is happening and there will be a series of Interim Care Orders granted. The Local Authority has to present its plan for the child as part of the proceedings, so it needs to be clear at this stage that the plan is to place the child for adoption. (Not all care proceedings will have the plan as adoption). Parents retain parental responsibility (a legal term which means they still have rights to make decisions for the child) and are parties to the proceedings. The Courts will always expect contact with parents to continue and will even dictate how frequent this should be. Grandparents are of course not automatically 'parties' in the proceedings and have no automatic rights.
Once a full Care Order has been made, the Local Authority then has to apply for a Placement Order which will allow them to 'place the child for adoption'. Contact with parents will continue but will be at the local Authority's discretion and will usually begin to reduce significantly, although an 'open adoption' will have the terms of future contact specified in the terms of the Placement Order.
Parents retain some rights unless and until an Adoption Order is made, although their rights are naturally limited by the fact that the child has been removed from their care by order of the Court.
For children who have been abused and where there is no possibility of a return to their families I agree that adoption can be an amazingly positive move and one which it is a privilege to be involved in as a worker. However, these children are sadly often so damaged (I hate referring to children as damaged but I can't think of another way to put it) that the task of finding appropriate adopters is well nigh impossible, and they can face the double disadvantage of having no sense of permanence coupled with the loss of contact with family members who may never be able to care for them but still love them dearly. I am not sure at what stage chadsky's granddaughter is but there is always hope that the process can be halted or diverted while the Court process is ongoing.
I hope I have answered your question Faye, probably a case of too much information!! You will know better than to ask again, once I start I find it hard to shut up!
Anyway, I am off to work now. My main job at the moment is working for the Social Work out of hours team, covering emergencies at nights and weekends, hence my username. However, the older I get I must confess to feeling less of a natural night owl than I used to be, and I would like nothing more than to be tucked up in bed with my book. Ah well, have to pay the bills....
and any other lurkers please join in, we dont bite. 
