What if you're purchasing a house and the previous owner wishes to reclaim some of the objects in your house? Wouldn't all the objects now be owned by the current owner, and if not, what kind of objects can be reclaimed?
When selling a residential property in the UK, you normally fill out a form called the TA10 Fittings and Contents Form, which outlines everything in the property included in the sale. This isn't a legal requirement, but your conveyancing solicitor will normally recommend it.
Anything else left in the property after the completion of the sale is still, legally, a possession of the previous owner and the new owner is obliged to inform them of these possessions in writing.
So, you do have to return it (and most people in such situations do return the possessions without question). However, if the presence of those possessions means you can't be reasonably expected to move into the property, then you can claim compensation from the previous owner for alternative accommodation (i.e. a hotel) until the situation is rectified. Or if the previous owner refuses to collect the possessions, you can likewise claim compensation for the costs of disposing of it.
Alternatively, if they do want the possessions back, but take their time getting it, you can charge them fair storage costs.