These are meant as a guide only and results can vary from oven to oven. Things to bear in mind:-
It is important that the joint is at room temperature when you put it in the oven. Cooking time will be increased if you put it in straight from the fridge
Always preheat the oven
A joint on the bone will cook more quickly than a boneless joint as the bone conducts heat
The joint should be allowed to rest for at least fifteen minutes once it is cooked. This allows for the hot juices to seep back into the meat giving even juiciness throughout and allowing the muscle fibres to relax making the meat easier to carve and more tender
Beef (Sirloin, Fore Rib, Wing Rib, Fillet)
To cook all joints to brown, roast in the oven for 20 mins at 200°C / 425°F / Gas Mark 7 PLUS …
For rare meat – 35 minutes per kilo (or 15 minutes per lb) at 160°C / 325°F / Gas Mark 3
For medium meat – 45 minutes per kilo (or 20 minutes per lb) at 160°C / 325°F / Gas Mark 3
For well done meat – 55 minutes per kilo (or 25 minutes per lb) at 190°C / 375°F / Gas Mark 5
Pork (Loin, Leg, Shoulder, Belly)
Initially cook for 30 minutes at 220°C / 425°F / Gas Mark 7 then for 25 minutes per lb (or per 450g) plus 25 minutes at 190°C / 375°F / Gas Mark 5
Lamb (Leg, Loin, Best end or Rack, Shoulder, Saddle)
Initially cook for 20 minutes at 220°C / 425°F / Gas Mark 7 then reduce the oven temperature to 190°C / 375°F / Gas Mark 5 and cook for 20 minutes per lb (or per 450g) to achieve slightly pink meet. If you like your lamb well-done leave your joint in the oven for an additional 20 minutes.