Download and print the templates from sewmag.co.uk. Using the outer fabric, cut out one top piece, one front, one back and two covered zip pieces. From the lining fabric, snip out one pocket, one top piece, one front and one back. Press a 1cm hem on each side of the pocket, pin centrally on the right side of the lining back piece and sew round three sides, leaving the top side open. Make some extra stitches at the top corners for strength, then set aside.

Trim the zip to 44cm, then press a 1cm hem along a short side of each of the zip covers and open out so a crease is visible. With the right side of the fabric facing the right side of the zip, position the cover over an end of the zip, meeting up the unfolded end with the end of the zip. Hand stitch along the fold line, then flip the fabric over, so the right side is facing upwards. Make a few stitches along the raw ends to hold in place. Repeat for the other end of the zip.

Pick up the top pieces in both the lining and outer fabrics. Tack a length of piping along edge A of the right side of the outer fabric, meeting up the raw edge of the fabric with the raw edge of the piping. With right sides facing, pin, then tack the piped edge A to one side of the zip, ensure the zip is closed, with the slider positioned to the left hand side. Turn the tacked pieces over so the reverse is showing.

Pick up the lining piece, then pin and tack edge A of the lining along the reverse (but the same edge of the zip as before), in order to tack through the outer fabric, zip and lining. Use a zipper foot to machine sew along the tacked lines, remove tacking and turn through to the right side. Pick up the front pieces, then tack piping to edge C of the outer fabric piece.

With the right side of the fabric facing the right side of the zip, tack the piped edge along the opposite side of the zip just worked. Turn over and tack edge C of the lining to the reverse of the zip worked before. Stitch through all layers, remove tacking and turn through to the right side.

Cut out two 4cm x 5cm rectangles with a scrap of outer fabric. Fold in half lengthways and sew down the 5cm edges. Turn through to the right side, then move the seam to the centre. Fold in half to make a loop and add on a D-ring. Tack the raw edges of the loop to the raw edge of one end of the zip. Repeat for the opposite side.

Lay the zipped top and front section flat with the right side facing up, then open the zip. Position the outer back piece, with the right side facing down, directly on top. Tack all round, securing the outer back piece to every part of the outer top and front. Tack through all layers, including the lining along the top edge of B; but then leave D, the curved edge of the lining, to hang separated at the back. Stitch where tacked and remove tacking.

Turn the bag over and lay the lining back piece, with right sides facing, on top of the already sewn lining pieces. Tack all round, tacking through all the layers of the top edges, separating the curved edge D of the lining from the outer fabric. Leave a 10-12cm gap along the bottom of edge D for turning through. Sew where tacked and remove tacking. Turn all through to the right side and close the lining gap with whipstitch or running stitch. Put the lining inside the outer.

Pick up the webbing. Singe or fold over and sew the ends. Thread one end through the middle bar of a tri-glide bar adjuster. Bring this end back to the webbing and stitch so the tri-glide bar is secured and hanging at one end. On the opposite end slot on a swivel clip, let it hang around the middle of the length of webbing.

Slot the open end of the webbing through the middle of the tri-glide bar as before and move the bar along enough to attach this end to the other swivel clip. Fold the end over and sew to secure. Adjust the length of the strap by moving the bar up and down, turning the bag from something worn on the waist to a bag which can be worn across the body. Clip the ends to the D-rings on the bag.