For the relish
Grease and line the bottom of a 700g/1 1⁄2lb loaf tin. Preheat the oven to 180°C/350°F/Gas mark 4.
Melt the butter in a large pan, and add the minced beef, onion and garlic. Sauté, stirring, for 7 minutes until the meat is brown and sealed.
Transfer the mixture to a bowl, and add the remaining ingredients. Mix well, season and spoon into the prepared tin. Cover with foil.
Stand the loaf tin in a roasting tin, and add 2.5cm/1in of water. Carefully place in the oven and cook for 1 1⁄2 hours.
Mix together the relish ingredients in a bowl. Turn out the meatloaf and garnish with the fresh thyme. Serve with fresh vegetables and the relish as a condiment.