Roasted tomato soup with summer herbs

This is our summer soup, almost the only one we serve hot for about five months. Not that summer in Ireland lasts five months, more like five days in May usually, but ripe well-flavoured tomatoes keep coming, right up to late October. It is easy to make and has a simple but intense flavour - ripe, roasted tomatoes, set off by whatever herbs you have to hand. Again, keep it simple; most of the time we use basil, oregano and parsley, no more. The passata (sieved tomatoes in a carton available