Preheat oven to 200C/180C fan/gas 6 and put a baking tray in to heat.

Put the chicken, tomatoes and mozzarella in a bowl and stir in the pesto. Season well.

Brush 1 filo sheet with butter. Lay a second sheet on top, brush with butter, then top with a third filo sheet. (Keep remaining filo covered with a damp tea towel while you work.) Halve the filo stack lengthways. Place 2 heaped tablespoons chicken mixture along the shorter edge. Fold in the sides, then roll up. Before you get to the end, brush with a little butter to seal the seam.  Repeat with the remaining filo pastry and chicken mixture to make 8 parcels.

Transfer the parcels to the preheated baking tray, seam-side down. Brush with remaining butter and bake in the oven for 25 to 30 minutes until golden.