A connection member intended to be used for the assembly of metal tubes to form a demountable metal frame of a relocatable building, in particular a farm building, the connection member comprising a first part of the connection member and a second part of the connection member which are designed to be removably assembled by removable fastening means at a first assembly operation, wherein: - the first part of the connection member comprises a first guide channel and a second guide channel , - the first guide channel being intended slidingly to receive an end part of a first metal tube , - the second guide channel being intended slidingly to receive an end part of at least one second metal tube , the second guide channel being positioned substantially perpendicular to a central portion of the first guide channel , - the second part of the connection member comprises a third guide channel having a transverse through opening , - the third guide channel being intended, together with the second guide channel , slidingly to receive an end part of at least the second metal tube , - the transverse through opening being intended, together with the first guide channel , slidingly to receive an end part of the first metal tube and wherein: - the first guide channel , the second guide channel and the third guide channel each have a U-shaped cross-section or similar with a web bordered by two opposite-facing side flanges and also wherein, at the first assembly operation: - the connection member is designed to surround the first metal tube and the at least one second metal tube , so that: - the opposite-facing side flanges of the third guide channel cover all or part of the opposite-facing side flanges of the second guide channel , and - the transverse through opening extends opposite all or part of the central portion of the first guide channel . - the first part of the connection member comprises a first guide channel and a second guide channel , - the first guide channel being intended slidingly to receive an end part of a first metal tube , - the second guide channel being intended slidingly to receive an end part of at least one second metal tube , the second guide channel being positioned substantially perpendicular to a central portion of the first guide channel , - the second part of the connection member comprises a third guide channel having a transverse through opening , - the third guide channel being intended, together with the second guide channel , slidingly to receive an end part of at least the second metal tube , - the transverse through opening being intended, together with the first guide channel , slidingly to receive an end part of the first metal tube - the first guide channel , the second guide channel and the third guide channel each have a U-shaped cross-section or similar with a web bordered by two opposite-facing side flanges - the connection member is designed to surround the first metal tube and the at least one second metal tube , so that: - the opposite-facing side flanges of the third guide channel cover all or part of the opposite-facing side flanges of the second guide channel , and - the transverse through opening extends opposite all or part of the central portion of the first guide channel . <EOS>