Shed or caravan?

Well, technically, it's a caravan. Designed by Buckley Gray Yeoman for Retreat Homes, this is how they explain it:

"Technically, it is a caravan and conforms to the definition of a Caravan as set out in the Caravan Sites Act 1968. It is also built to British Standard BS/EN 3632. It is therefore exempt from Building Regulations and VAT (apart from any furnishings, upon which VAT is applied). Classified as a transportable building, it is ready to move into within days and can be situated in places that a conventional home cannot. The Retreat is also National Caravan Council (NCC) approved."

So could it go in the garden?

"A Retreat may be sited within the grounds of a dwelling house, without the need for planning consent, provided that:
* - It is legally a ‘caravan’ (ie: it complies with the definitions within the Caravan Sites and Development Act 1960 and the Caravan Sites Act 1968).
* - The caravan is sited within the curtilage of the dwelling house.
* - The caravan is sited for a purpose incidential to the enjoyment of the dwelling house as such."

Although it's aimed at a holiday home market, there is a garden office option. It's FSC timber, with floor to ceiling windows, oak floors and kitchen or bathroom options, plus furniture suggestions. Thanks to Tim Baber for spotting this at the Grand Designs Show.