There are probably many other examples like the two listed here. But I was just wondering how the Competition Commission becomes involved in the first place and how they deem certain supermarkets to be too close.

Another example of where a supermarket has apparently been knocked back by the Competition Commission is Tesco at the Metrocentre. For years they have been trying to open a store there, usually rumoured to be site of the ex-Marks and Spencer/ILVA store opposite ASDA or opposite the Coach Park on the wasteground as you're driving towards Costco. But the location of the Tesco in Gateshead high street (pre-revamp) has allegedly prevented this from happening. However, Tesco have finally managed to gain a presence at the Metrocentre. They're opening one of their Metro stores in the Blue Quadrant near the Interchange where Milligans used to be.