The classic deformation known as simple shear has been investigated within the framework of nonlinear elasticity for isotropic incompressible hyperelastic materials in a large variety of contexts, most notably in the analysis of the mechanical behaviour of soft matter. One of the major difficulties in providing a realistic physical interpretation of this idealised homogeneous deformation is the fact that the conventional mathematical model of simple shear using a plane stress assumption to determine the hydrostatic pressure implies that a normal traction must be applied to the slanted faces of the deformed specimen. However, such a traction is not applied in practice. To resolve this dilemma, we retain the classic plane stress assumption to determine the hydrostatic pressure but modify the basic kinematics to consider a simple shear deformation superposed on a uniform lateral extension or compression of the specimen. The amount of lateral stretch is treated as a stabilising factor determined so that the predicted normal traction is minimised and thus the fidelity of the model with experimental protocols is enhanced. This new approach is illustrated for a variety of classical strain-energy densities for isotropic hyperelastic materials that have been used to model the mechanical behaviour of soft matter.