  We consider singularly perturbed boundary value problems with a simple
interior turning point whose solutions exhibit an interior layer. These
problems are discretised using higher order finite elements on layer-adapted
piecewise equidistant meshes proposed by Sun and Stynes. We also study the
streamline-diffusion finite element method (SDFEM) for such problems. For these
methods error estimates uniform with respect to $\varepsilon$ are proven in the
energy norm and in the stronger SDFEM-norm, respectively. Numerical experiments
confirm the theoretical findings.
