Neighbourly matters refer to a range of issues that arise between property owners and their neighbours when there is a potential for their respective property rights or interests to be affected by things such as construction, renovation, access, oversailing or any other type of development. 

In the UK, this includes, but is not limited to, party wall agreements, rights to light, scaffolding and crane oversailing  and boundary disputes. Handling these matters carefully is vital to maintain good relations between neighbours and ensure compliance with UK laws to avoid risk of litigation and construction delays and increased costs

 A party wall is a wall or structure that stands on the land of two or more owners. This could be part of a building, a garden wall that spans two properties), or a floor dividing  a duplex or flat. It can also be a wall in single ownership, where a neighbour takes structural support of the wall, creating parts of, or sections of a wall that are party under legislation. 

Party walls are governed by the Party Wall etc. Act 1996 in England and Wales, which provides a framework for notifying neighbours of intended works, preventing and resolving disputes concerning party walls, boundary walls, and excavations near neighbouring buildings.

A party wall can serve various purposes, dependent on its location and adjoining structures. It separates buildings owned by different parties and also supports the weight of any part of a building, and facilitates the attachment of two adjoining walls. . The function of party walls, especially in urban areas, is crucial for allowing full site development,  defining property boundaries and supporting the structural integrity of buildings built in close proximity to one another. 

You cannot unconditionally stop a neighbour from undertaking construction on a party wall if they follow the legal process outlined in the Party Wall etc. Act 1996. The act is an enabling Act, which allows a building owner to undertake works that without the act, they would find difficulty, legal challenge, in undertaking. 

 However, they can influence how and when the work is done. The Act provides a framework for peoples right to be protected via notification procedures,  express consent or dissent and ensures that any works carried out are reasonable and do not cause unnecessary damage or inconvenience to an adjoining owner.

Tenants do not typically have the authority to stop  party wall works directly, as the Party Wall etc. Act 1996 deals primarily with property owners. But tenants with more than 12 months legal interest in a property are deemed an owner under the act. In this case they will receive notifications under the act and have their rights protected. However, tenants of less than 12 months should be informed by their landlords about proposed works, and their practical concerns should be considered.  The terms of conditions of any tenants’ lease/or licence to occupy should also be reviewed. As express rights and procedures may be contained in any such contract between a landlord and a tenant. 

 If the planned extension involves work on a party wall or falls within the types of works described in the Party Wall etc. Act 1996, then your neighbour must inform you in writing, and you both must either expressly agree to  the work or resolve the dispute that arises as outlined by the Act. 

 If the work  takes place wholly  on your neighbour's land and does not fall under the definitions of the Act then  a party wall agreement may not always be required.

 In the UK, the legal right to light is an easement that gives a landowner the right to receive natural light through defined apertures (windows or openings) in a building, over the land of another property. If a new development significantly interferes and blocks this light, then an affected property owner may have the legal grounds to object to the development and prevent the obstruction occurring. Ie stop the development or parts of the development that are blocking the light. 

The 20-year rule for rights to light refers to the principle that if a window (or another opening) has received uninterrupted natural light for 20 years or more, it then gains an absolute right to light under the Prescription Act 1832. This means the right to light is established, and any development that unreasonably infringes upon this light could potentially be stopped and asked to be removed under law.