1 Download the template at sewmag.co.uk, print and follow the cutting guide. Position the pocket bags along the slanted edges of the front trouser pieces, right sides facing. Match the notches, pin and stitch across. Turn the pocket bags wrong sides out, tease out the seam and press. Position the back pocket pieces behind the bags, matching the curves, making sure that the side edges are running smoothly below the pocket edge.

2 Pin and stitch from the top waistline around the pocket bag to the side seams, then neaten the edges. Press the pockets flat, then stitch the pocket layers to the trousers at the side edge and waistline, keeping the stitching within the seam allowance.

3 Match the two front trousers together around the centre front crotch, then sew and neaten the seam allowance and centre back crotch seam edges. Match the seam together and stitch as far as the zip notch. Sew the darts into the back trousers and press towards the centre back.

4 Lay the front trousers over the back trousers, right sides facing. Match the side seams together, then pin and stitch. Neaten the seam allowance and press towards the back of the trousers. Match the inside leg seams and sew in one continuous seam. Neaten the seam allowance and press towards the back of the trousers.

5 Fuse the interfacing to the waistband and neaten one of the long edges. Position it along the waistline of the trousers, matching the raw edges together; the centre back edges of the waistband will run in line with the centre edges of the gap left for the zip in the back of the trousers. Pin in place, then stitch.

6 Sew the concealed zip into the centre back opening and up half of the waistband, using a regular or concealed zipper foot. Fold and press the seam allowance along the two sides of the opening. Open the seam allowance and, with right sides facing, place the open zip face down, matching the teeth to the crease line in the seam allowance, and pin.