All organic matter decomposes given time. Letting time do the work is sometimes referred to as "cold composting". A certain amount of heat is generated but worms do much of the digesting. Then again there is "hot composting" which is quicker. Raising the temperature increases decomposition by microbial activity. Indeed it may become too hot for worms though they will return if the pile cools.

 "Hot bins" can be purchased made from thick polypropylene which retains the internal heat and insulates from external cold. But they cost about £200 so I decided on the DIY approach using two spare "Dalek" bins, one slightly smaller than other.

 

  I lagged the smaller one with some insulation material left over from another project. Basically it's a tougher version of bubblewrap with a layer of foil on both sides. Then I put the larger bin over the smaller thereby creating a double wall bin insulated in the middle.

 

  I doubt it will get as hot as a purpose made hot composter but I'm happy to let time play its part. In any case if it speeds up the initial composting I will transfer the contents to another bin for the worms to finish.