Over high heat, in a smoking hot pan, caramelised the beef cubed, in batches, on all sides with some rapeseed oil. Season with salt and pepper and remove from the pan into the slow cooker bowl.
With a wooden spoon, scrape the pan content and transfer into the slow cooker bowl.
In the slow cooker bowl, add the onion, garlic, carrots, leek , celery, herbs and season well with salt and pepper.
Add the tomato purée and pour in the water.
Stir all the ingredient and cover the slow cooker with the lid and cook for 8-9 hours on low.
Check the seasoning and serve with some mash or boiled potatoes.