Preheat the oven to 200°C/180°fan/Gas 6
Cut the crusts off each slice of bread, then gently roll out each slice, using a rolling pin, to make it thinner
In a small saucepan, gently heat the butter and tomato ketchup together until melted, then stir in the mustard
Brush some of the butter mixture over one side of each slice of bread, then place a sausage diagonally across each one
Bring the opposite corners up and over the sausages to meet in the centre, and secure with wooden cocktail sticks
Place on a baking tray, brush with the remaining butter mixture and bake for 30-40 minutes until the sausages are cooked
Check halfway through cooking and if the bread is browning too much cover with strips of foil.