We probably spend around 100 quid a week for a family of three but could get it down to less if we cut down on certain luxury foods we enjoy. We manage breakfast, lunch and dinner on what we spend
Tops tips:
Keep the protein vegetarian most days of the week: lentils, beans etc (dal, veggie chilli, minestrone, lentil shepherds pie etc)
eggs eggs eggs: frittata, cheese and veggie-filled omelette, crustless quiche is a fantastic way of using up veggies
frozen fish: cod, haddock, salmon, prawns etc all cheaper than fresh
buy whole chicken and do a couple of roasts a week. If you eat meat buy more lean mince - you can make burgers, chillis and British classics.
potatoes, pasta and rice for filling carbs (do a roast veggie traybake with potatoes a couple of times a week - cheap, tasty and nutritious
stick to seasonal and local foods (imported is more expensive) and eat more traditional local dishes: in the UK this means mainly green veggies such as cabbage and broccoli, peas, carrots, spuds, berries in season or frozen, apples. Build your recipes around these ingredients and rediscover old favourites (roasts, shepherds/cottage/fish pies, apple crumble etc).
oats oats oats - not only are these cheap and nutritious, they are also extremely versatile: porridge, overnight soaked bircher muesli, cookies, granola and also savoury (cook with olive oil, parmesan cheese and add a fried egg, onion, tomato, green veggies or whatever you fancy as a cheaper and easier alternative to risotto that will also help you to sleep better!)
build a spice and herb pantry: essential spices and herbs include pepper, cumin, turmeric, smoked paprika, curry powder, oregano, thyme, bay leaves, rosemary and mustard.
buy strong-tasting, hard cheeses as it will go further and last longer: parmesan, pecorino, extra mature cheddar etc.
And finally adapt recipes to the ingredients you actually have!