1. Place all the marinade ingredients in a blender and process until smooth.

2. Rub the beef with salt and pepper before pouring over the marinade. Put the beef and the marinade in an air-tight plastic bag and leave overnight in a cool place.

3. Preheat the oven to 200C/gas 6. Remove the beef from its bag and place in a roasting tin. Spoon over a couple of tablespoons of the marinade.

4. Roast the beef for 30 minutes, longer if you prefer the meat well-cooked. Spoon over the juices once or twice during cooking.

5. While the beef is roasting, make the salsa. Tip all the salsa ingredients into a blender and process until smooth. Taste for seasoning and serve at room temperature with the hot roast beef.