Sir: Rob Brown’s article ‘Meet the Imbys’ (11 August) did not point out that residents in favour of a new supermarket often see short-term benefits without being aware of longer-term consequences.

There are many examples of towns that have been decimated by the arrival of a large supermarket. Often, residents naïvely expect it to arrive without smaller shops being affected. But in a mature market, a new supermarket will take most of its sales from existing retailers, threatening their existence.

Another issue is the number of new jobs promised, which is almost always highly optimistic. In your article, Tesco is quoted as saying that that in Sheringham, a 4,000 sq ft store will create 150 new jobs - really? Just how many full-time equivalents does it take to run a store of this size? And how many of these “jobs” will actually be zero-hour contracts providing the occasional shift?

The Localism Act will undoubtedly give local people more say over supermarket developments. Highly professional supermarket store development teams will be up against local people usually facing this type of planning issue for the first time.

If every new supermarket impact assessment was published, then local people could see that the butcher and baker in their town was expected to lose 25% of their business and that a village shop five miles away would lose £2,000 per week. This would allow local people to make a more balanced judgement of the long-term costs and benefits of a new supermarket to their community.

Kenneth Parsons, chief executive, Rural Shops Alliance