Fabric, 1.5m (1.45m wide)InterfacingBias binding, 1.5mOne 1.5cm button
Back: cut one pairBack neck facing: cut one pairFront: cut one on the foldFront neck facing: cut oneButton loop: cut one 2cm x 10cm strip from fabric on the bias1.5cm seam allowance used throughout.
Apply interfacing to the reverse of all the facing pieces. Stitch each end of the front neck facing piece to a back neck facing piece, right sides together. Fold the button loop strip in half lengthways, right sides together, pin, then sew along the raw long edge with a 5mm seam allowance. Turn right sides out, then press.
Neaten the raw edges of each back piece at the centre-back, side and shoulder seams. Join the pieces at the centre-back, up to the upper notch. Neaten the raw edges, then stitch the bust darts in the front piece.
Join the front and back pieces at the shoulder seams, right sides together. Check the button loop is long enough for the button, including the 1.5cm seam allowance. With raw edges matched, pin the loop 1.5cm below the raw neck edge, then stitch.
With right sides together, pin the neck facing to the neck edge, matching the seams. Fold the centre-back seam to expose the stitching, then pin so that the seam lines are aligned. Stitch the neck facing, starting at one side of the back opening and finishing at the other. Trim the seam allowance, clip the curves, then turn the facing to the inside.
Understitch the back neck facing as close to the centre-back as you can. Pin the bias tape to the armhole edge with right sides together and raw edges matched, then stitch in the crease. Press the bias tape to the inside and stitch close to the folded edge. With right sides together join the side seams, then sew a button at the upper back neck opposite the loop.