Sir - In the last couple years, a new form of visual pollution is affecting many parts of Oxford. As a resident of Jericho, I am faced in almost every street with a variety of notice-boards attached to houses, some saying For Sale' or To let' and others (the largest proportion) saying Let'. I have seen a similar situation in East Oxford, and can only assume that it exists largely because these areas are attractive to students and other temporary residents.

Whereas I can see that estate agents needing either to sell or to let need to advertise those properties, and whereas I can accept (at a pinch) that there may be a need to advertise their sale or rental for a short time afterwards, I cannot accept that once a house is let there is any justification for the notice-board to be changed to Let' to provide free and continuing advertising, totally free of charge.

I have actually had a conversation with one of the estate agents whose board has been defacing the house next door to mine with a Let' board for weeks, and she candidly admitted that the sole purpose of its being there is free marketing.

I do not have time to waste on counting the number of Let' notice-boards from one specific and locally-based estate agents, but I would bet that they are in double figures in this small area.

I would be interested to know from those responsible in the city council what the situation is regarding this visual pollution which is only likely to grow, what with the credit crunch and the difficulties in the housing sector.

Joelle Mann, Oxford