A method of radially expanding a tubular element comprises inducing the wall of the tubular element to bend radially outward and in an axially reverse direction so as to form an expanded tubular section extending around an unexpanded section of the tubular element. The bending process occurs in a bending zone of the tubular element, and the method further comprises progressively increasing the length of the expanded tubular section by inducing the bending zone to move in an axial direction along the tubular element.