Peel and finally chop the onions. Peel and finely chop the garlic. Halve the peppers and scoop out the seeds and white pith. Chop the peppers into 1cm-thick pieces.
Place a large pan on the heat for a few mins. When warm, drizzle in 2 tbsp oil and add the onions. Cook on a low heat for 6 mins, stirring often, till slightly softened and lightly coloured.
While the onions are cooking, peel the sweet potatoes. Chop them in to 2-3cm-thick chunks. Trim and peel the carrots then chop them into 3cm-thick slices.
When the onions are browned, add the garlic and peppers to the pan along with 1 heaped tbsp jerk seasoning. Cook, stirring for 2 mins till the pan smells aromatic.
Add the carrots and sweet potatoes to the pan with the pearl barley and stir together. Add a generous pinch of salt and pepper.
Tip in the tins of chopped tomatoes and 800ml water. Bring to a bubble, then turn the heat to low. Simmer for 30 mins till the pearl barley is tender and the veg are soft. Stir every now and again to stop it sticking to the bottom.
Taste the stew and add more salt and pepper if you think it needs it. Serve in warm bowls.