You'll find all your legal obligations in a booklet published by the Department for Work & Pensions. It guides you through the essential steps of getting a medical certificate, registering the death and sorting out property and possessions. To get a free copy, visit your local benefits office or go online:
DWP1027 What to do After a Death in England and Wales
Or for Scotland;
D49S What to do After a Death in Scotland
There are very few regulations covering the disposal of a body within the UK. For now you must undertake either to bury or cremate it, (click here for potential alternatives) and you must have a death certificate signed by a doctor and a Certificate for Burial or Cremation from the Registrar of Deaths. This last document is very important, and most hospitals and mortuaries will not release the body until they've seen it.
If you're doing it yourself, you'll have to hunt for information that's obvious to professionals. Some undertakers offer advice, for which they charge - but if the burial or cremation is at a local authority cemetery or crematorium, their management can advise you on how to proceed as well.
Either way, there are certain things you'll need to sort out for yourself, such as deciding whether the service is to be at a cemetery, crematorium chapel or other building (not necessarily religious); booking the slot and appointing and briefing an officiant if desired to deliver the service; arranging music and transport for the coffin, mourners and floral tributes; and grave-digging, if necessary. The logistics can be daunting, but the rewards for producing a totally personalised funeral for your loved one can be immense.