Preheat the oven to 180°C.
Trim the venison and rub with olive oil, salt, pepper, and dried thyme.
Wrap the loin tightly in the pancetta slices using cling film to help.
Sear the loin in vegetable oil in an ovenproof pan until the pancetta is golden-brown.
Roast the venison in the oven for 6 to 8 minutes until pink inside.
Reduce sloe gin in the pan, then simmer with beef stock and juniper berries for 5 minutes.
Strain the sauce and cook with blackberries until softened and slightly crushed.
Whisk in the butter and season the sauce with salt and pepper.
Slice the venison loin into thick pieces.
Serve three slices per person drizzled with the blackberry glaze.