If the shed has been on adjoining land owned by a private individual for 10 years of the land is registered at the land Registry or 12 years the property is not registered at the land Registry then you can apply to the land Registry to have the land registered as yours on the doctrine of adverse possession. You would need of the length of time that the shed had been there and that you had exclusive use of it, this latter point of being not difficult to prove.
Then, you would be entitled to have the land on which the shed rests registered in your name with possessory title.
However if the adjoining land is not owned by a private individual but by the local authority, the period goes up from 10/12 years to 30 years. Land owned by the local authority is land owned by the government which is deemed to be Crown land.
You would therefore need to prove that the shed had been in place for over 30 years before you could claim the land. If the local authority decided they wanted to oppose that because you had no proof, it could be an expensive battle at the land tribunal costing several thousands of pounds even though you may ultimately win.
At this stage your best option is probably to move the shed although you cannot be compelled to replace the fence .
You may have a claim against the seller of the property if this land is particularly desirable valuable to you if as part of your precontract enquiries, it was stated that you owned this part of land. It seems unlikely that would be the case because otherwise it would be outlined in red on the land Registry title plan which the solicitor would have sent to you to confirm the extent of the area that you were buying.
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