Getting planning permission for a new house in the garden

[Ruralbliss]

I've got no intention of building a house in my garden but thinking laterally on the day my buyers pulled out.

House has huge garden with enough land for another house or bungalow.

Where would I start to find out about feasibility (effort/time/costs etc) to obtain - maybe an architect?

Has anyone here ever done this? Does it add value to a house or does it render it unsellable to normal people most of whom aren't looking to build in their garden.

This is probably a really daft idea.

First thing to check is if Council have a Policy on back garden developments

We can phone the local planning dept and they have a duty planning officer who will answer your questions.
The main things I would guess are access to a road - can you do that without causing eg a dangerous entrance on a roundabout as that wouldn't be allowed. Are you over-looking others. Would the house need to be a special design to fit with other existing properties.

I am a town planner, you need to phone your local council's duty planner. There should be one available usually on a morning or afternoon.
Not sure how residential your area is but this is not usually very easy. Has anyone else in your street done similar? If so, I may set a precedent.
To add value to your house sale you could sell the house with planning permission for a second house.

I would assume it adds value, and would attract developers, though it would put off those who are just interested in the house.

We saw a house locally that has permission for 4 houses in the garden. Love the house, love the garden, no interest in building new properties or having 4 more houses on the doorstep. It’s still for sale. Perhaps developers and builders are more cautious at the moment, as their margins will be squeezed by the spiralling cost of materials and long delivery times?

I would urge caution as per above comments. If I saw a house with pp for building in the garden, I'd immediately ask myself if the neighbours were likely to do the same and if the house I'd buy would retain its value.
Secondly building one house is hard to make money given spiralling costs at the moment but if you could fit in more, it might be worth considering.

Yeah I think I'd agree with the above - as a normal buyer I would be very put off with buying a house that came with planning for another house - you will restrict your buyer pool to a very specific group of people.
Still worth investigating though - land with planning has a high value - you could always sell it separately, or get financing to build the bungalow yourself & sell 2 individual properties.