Estate agents may have to get council permission to put up For Sale signs.

Councillors are looking at ways of cutting the number of estate agency boards in historic squares and streets.

One idea being considered is making estate agents apply for consent before putting sale boards outside Grade I and Grade II* listed buildings.

Before taking any action, the council will have to consult with the estate agents' association, residents' groups and conservation societies.

There is already a voluntary code of practice restricting agents to one board per property in historic areas.

But a council survey revealed a third of the boards in Brunswick Place, Hove, breached the code.

It found there were 30 boards in Brunswick Place, a street with only 70 houses. The number of boards displayed in Brunswick Square has risen by 50 per cent in the last two years.

Councillor Chris Morley, who chairs the environment committee on the city council, said: "We know this is of concern to residents. We want to respond."

The impact was slight in some streets and the voluntary code of conduct helped.

But he said: "With the property market so buoyant, there are now many new agencies not signed up to the agreement.

"Where buildings have been converted into a number of flats, it really can be quite obtrusive."

Restricting boards has worked well in other historic cities such as Bath, where there are 5,000 listed buildings. There, the majority of the city has controls on boards.

John Small, secretary of the Regency Society, said it would be better to ban boards altogether from areas with Grade I buildings such as Brunswick Square and Sussex Square.

But he thought the council's proposals might be better suited to other areas where there were listed buildings.

Mr Small said there was a real problem with boards and they could spoil the appearance of magnificent buildings.

Nick Hayward, manager of Fox & Son in Church Road, Hove, said: "Amazingly enough I am not against it. I often think a sea of boards is not always the most attractive thing to look at.

"At the moment it is seen as part and parcel of the industry but if everyone across the board had to abide by the same rules, there would not be an issue of competition. It would be a fair process and I would not have a problem with it."