difference - "Mobile homes" in American and British English

I'm always getting these types of mobile homes mixed up. Could someone please explain the difference between the following?

1. A mobile home. Is this any home that can be towed by a car? Is this commonly used in both dialects?


2. In the US: recreational vehicle sometimes called an RV.
   
   Which of the two names is more common in the US? Are British people familiar with this term? If not, what's the most common name for this type of home in the the UK?


3. 
   

   A caravan, either the colourful gypsy caravan, or the British English one. I don't think Americans use this term. What would it be called in the US? Is it No.4?

   
   


4. 
   

   A trailer is this also another name for a "recreational vehicle"? What's the difference?

   
   


5. 
   

   In Italy the term ‘il camper’ is used for most types of holiday homes driven by motor vehicles. Do British people and Americans use this term? What is the difference between a camper and a caravan? Is one term more outdated than the other?

   
   

Answer

I can give you a British English definition as I own such vehicles...

A caravan is a trailer towed by a car:

A camper van (or campervan) is a van of ~1 ton converted for sleeping & cooking. These are typically VW Transporters or Mazda Bongos. There are still huge numbers of lovingly preserved VW campervans on the roads (I have a classic T2 and a T5):

A Motorhome is a purpose built vehicle, larger than a campervan. These are coachbuilt onto a commercial chassis. The chassis are usually Peugeot or Fiat. They come in varying sizes but are rarely more than 3tons:

You will find people "in the scene" who get very picky about how their vehicles are described. Some people will get upset if you refer to their motorhome as a camper for example.

We British do recognise the term RV as being an American equivalent. However, in Britain, when applied to British vehicles, the term is usually only used for the very large: