Peel and roughly slice the carrots. Slice the celery. Peel and roughly chop the onions. Peel and slice the garlic. Put a large pan on a medium heat and add a couple of lugs of olive oil. Add all your chopped and sliced ingredients and mix together with a wooden spoon.
Cook for around 10 to 15 minutes with the lid askew, until the carrots have softened but are still holding their shape, and the onion is lightly golden.
Put the stock cubes into a jug or pan and pour in 1.5 litres of boiling water from the kettle. Stir until the stock cubes are dissolved, then add to the pan with your tinned and fresh whole tomatoes, including the green stalks that may still be attached to some of them (these give an amazing flavour – trust me!) Give it a good stir and bring to the boil. Reduce the heat and simmer for 10 minutes with the lid on. Meanwhile, pick your basil leaves.
Remove the pan from the heat. Season with salt and pepper and add the basil leaves. Using a hand blender or liquidizer, pulse the soup until smooth. Season again before dividing between your serving bowls.