Pre heat the oven to 160 fan, 180 electric or gas 4.
Boil the kettle.
Place chicken in a roasting tin.
Take the ends off the lemons. Cut in half. And prick all over with a fork, right through the skin.
Season the chicken inside and out with salt and pepper.
Stuff the lemons into the cavity. If they don't all fit place cut side down in roasting tin.
Push the rosemary sprigs into the cavity around the lemons.
Pour boiling water all over the skin and fill up the roasting tray about a third to halfway.
Pop the stock cubes into the water, allow to soften and mash slightly.
Roast in the oven for one and a half to one and three quarters hours. Check the legs aren't pink.
Leave to rest in a warm place for 20 minutes, half an hour.
Remove the lemons and squash so that the juice goes into the sauce.
Strain into a gravy boat and serve poured over the chicken.