You don't need to have a religious ceremony - or any kind of ceremony at all - at a funeral. Some people may prefer a Humanist Ceremony. This type of ceremony is not intended to oppose a religious funeral, but to provide a dignified and respectful celebration of the death that has occurred. At this type of funeral, the services of an officiant or celebrant, to conduct the proceedings which can involve readings of appropriate prose, tributes by attendees or the officiant and the playing of appropriate music is normally used.
The British Humanist Association offers advice on all aspects of humanist ceremonies and produce a booklet Funerals Without God: A Practical Guide to Non-religious Funerals which can be purchased for £5 (including postage and packing).
Celebrants are trained professionals who can officiate at funerals, weddings, namings or any other rite of passage. For more information visit The International Federation of Celebrants
Alternatively, if you don't want a ceremony at all, members of the family or close friends can attend the committal, which can be in silence or with some music being played.