For a laugh, we planted up the seeds of a red pepper we had bought from the supermarket. For several weeks they did nothing, luring us into a false sense of disappointment that they would not grow. Then, all at once, they all did grow. All of them. We have ended up with 37 pepper plants. You can see them at the bottom of the photograph below. We had to buy more pots.
Due to their supermarket origins we have no idea what they will produce, recognisable or mutant fruits, or if they will take to the British weather enough to produce anything at all. I get the feeling they are all going to grow voraciously just to spite us.
It may be time to invest in a polytunnel.