Satellite dishes are blighting some conservation areas
More than 700 conservation areas in England are at risk of neglect, decay or damaging changes, English Heritage has warned.
Its survey of local authorities found plastic windows and doors, poorly maintained roads and street clutter were the biggest threats to the areas.
English Heritage is urging more to be done to save these places of special character which make England distinct.
It wants residents, local groups and councils to work together more closely.
In total there are 9,300 conservation areas in England from historic towns and villages and 1930 suburbs to rural idylls and industrial workers' cottages.
Each is designated by the local council for protection so its character and appearance can be preserved for local heritage.
But English Heritage's first ever conservation area survey found poorly considered home improvements and ill-thought out council work were putting 727 of these areas at risk.
All local authorities in England were asked about the conditions of their conservation areas, and 75% of them completed the questionnaire.
Dr Simon Thurley, chief executive of English Heritage, said: "Millions of us live in, work in, pass through or visit conservation areas. They are... the local heritage which gives England its distinctiveness.
"These are difficult economic times but our research shows that conservation areas do not need time-consuming or costly measures, just prioritising as places people cherish, the commitment of the whole council and good-management by residents and councils alike.
CONSERVATION AREA THREATS
Plastic windows and door: 83% of areas affected
Poor roads and pavements: 60%
Street clutter: 45%
Loss of garden walls, fences, hedges: 43%
Unsightly satellite dishes: 38%
Traffic calming measures: 36%
Alterations to front, roofs, chimneys: 34%
Unsympathetic extensions: 31%
Neglected green spaces: 18%
"Well-cared for, they encourage good neighbourliness, give a boost to the local economy and will continue to be a source of national pride and joy for generations to come."
He said he wanted to see councils make more use of their powers to protect "small but important original details such as windows, doors and front gardens".
"Lose these and slowly but inevitably you lose the character and the history that made the area special in the first place," he said.
He called for council departments, including highways and environmental services, and health and education teams, to work together closely to take better care of public areas.
He also urged residents to play a greater role by commenting on planning applications, helping prepare lists of local historic buildings or doing street clutter audits.
To coincide with publication of the English Heritage survey results, awards have been given to local authorities which have done the best work on conservation areas.
The overall winner was Stockton, in north-east England. Regional winners were King's Lynn and west Norfolk, South Derbyshire, Islington in London, West Lancashire, Southampton, west Dorset, Wolverhampton and Richmondshire.