Traditional 'shaped' coffins, made of hard oak or elm wood, have been used to bury people for years. Only since hardwood became expensive to buy, soft woods (such as pine), or 'chipboard veneered' coffins became the cheaper alternative. Although these coffins can be finished with handles, nameplates and ornaments made from metal, by far the majority now use brass or chrome look plastic instead - again in an effort to keep costs lower.
Chip board veneered coffins are by far the biggest seller at present, as they are strong and reasonably priced. Even though the industrial production techniques to make the chip board is not very environmentally friendly, as long as all the furniture is removed, they are bio-degradable.
Below are links to suppliers of traditional coffins. Although some will sell to you direct, for most, you may have to go through a funeral director.
www.coffincompany.co.uk (all sorts and designs available)
www.wealdencoffins.co.uk (stylish handmade curved design, can be hand painted or left natural)
www.wellscaskets.co.uk (specialist in childrens/babies caskets)