Sift the flour and salt into a bowl and stir in the walnuts.
Make a well in the centre.
Place the syrup, water and butter in a pan and heat gently, stirring, until the butter has melted.
Pour into the well in the flour mixture and beat thoroughly.
Beat in the egg to give a smooth batter.
Line a 12-hole bun tin with paper cases.
Spoon in the batter to two-thirds fill the cases.
Bake in a preheated moderately hot oven, 190°C (375°F), Gas Mark 5, for 20 minutes, until risen and firm to touch.
Transfer to a wire rack to cool slightly.
Serve warm, split and buttered.