Preheat oven to 300°F (150°C).
Salt and pepper the roast on all sides.
Heat oil in a Dutch oven over medium-high heat.
Sear the meat for about 2 minutes on all sides until nicely browned. Transfer it onto a plate.
Add potatoes, carrots and garlic to the pot, stirring over medium heat.
Stir in flour and then tomato paste. Mix until the flour and tomato paste is evenly distributed.
Add stock and Worcestershire sauce. Deglaze the pan, scraping browned bits from bottom of the pot.
Add the roast in the middle of the pot, pushing the vegetables to the side around the roast. Cover and place it in oven.
Roast for 3 hours, or until completely tender.
To serve, slice the roast against the grain, or shred using 2 forks. Serve with vegetables and gravy on the side.