Preheat the oven to 150C/300F/Gas 2.
Grease and line six square 22cm/8in tins.
Sieve the flour into the bowl of a large mixer fitted with the paddle attachment and add the sugar, ginger, bicarbonate of soda and salt. Mix well with a spoon.
Place the butter and syrup in a pan and heat until the butter has melted.
Put the eggs and milk into a jug and beat together until well combined.
Gradually pour the butter and syrup into the flour and mix, then add the egg and milk mixture and beat until the mixture is smooth. Pour into the lined tins.
Place in the oven for one hour or until a skewer comes out clean when inserted into the centre of the parkin.