lightisnotwhite Well there are laws to stop supermarkets becoming monopolies and industries forming cartels.
Energy and water providers do have direct government involvement..
This is a very good question. What you are describing is the regulation of competition. Its notoriously weak in the UK. There are very few competitors in the UK in the supermarket market, and many supermarkets have driven small players out of the market. They behave like monopolies in that they set the prices farmers, etc sell their goods to them in this country. e.g. dairy, eggs, etc..
Add to that the relatively poor regulation of planning. Government is in charge of planning and supermarkets or their subsidiaries buy up land and sit on it and wait for planning permission, a bit like the large housebuilders do. There are many obstacles to entering the market, not least the contacts necessary to be able to confidently landbank. Then theres retail parks. These are big money makers for local authorities, but they're really bad for the environment and often don't have any public transport links.
Who regulates the price landlords charge?
First of all the market and secondly the state. There is so much state regulation in the UK on the rental sector that it adds significantly to costs. It is naiave in the extreme to assume that George Osborne's massive increase of the burden on tax on landlords would not lead to a reduction in supply.
I have a student HMO in a city centre and I spend around 4k per year on regulatory costs and the ever changing requirements alone. I have to supply 11 different safety certificates/licenses. 20 years ago all that was required was a gas safety certificate. Those who use letting agents will also have to pay for the agent to attend each and every one of those inspections.
But anyway, in most successful cities anywhere in the world, accommodation is breathtakingly expensive. That is surely one of the marks of a successful city. The problem in the UK is more nuanced in that poor public transport infrastructure exacerbates the problem because people cannot effectively commute to cities in many cases.