Businesses fear a road closure will cut them off from customers and lead to serious financial losses.

A six-month closure of Greyhound Lane, between Eardley and Estreham Roads, starts in November to extend platforms at Streatham Common station, but shop owners said a partial closure of the road, which crosses the railway lines, has already badly affected them.

Jan Czarnopolski, owner of the family-run Village Card Gift and Balloon Shop, said takings were down by more than 50 per cent on the first day of the partial road closure.

He said: “When the bridge shuts were are going to be absolutely stuffed. It’s going to have a major impact on us and other businesses.”

He said the full closure would come during the busiest times of his year – Valentine’s Day, Christmas and Mother’s Day – and that his employees’ jobs were in jeopardy.

Ian Livermore, who owns Mrwebit, said businesses barely held on when Eardley Road temporarily closed in 2010.

He said: “To do this again without warning is really the thing everyone is amazed by. It really highlights the lack of communication between the council, companies and residents and businesses.”

Streatham’s town centre manager, Angelina Purcell, said: “Clearly we value the upgrade to the station, but the protracted works will no doubt have a serious impact on these small businesses, already struggling with the tough trading environment.”

A Network Rail spokesman said a public meeting will be held to discuss the works at Granton Primary School, in Granton Road, at 7pm on October 4 and said 12,000 leaflets would be distributed to residents.

He said: “Pedestrian access will be maintained and a shuttle bus service will connect both sides of the station.

“Any business wishing to make a claim for compensation should contact us and we will respond to each claim individually.”

There are also concerns among residents and commuters about traffic disruption, erratic driving and accidents in the area.

Neighbourhood Watch co-ordinator in Streatham South Helen Smith said: “Residents are concerned because there have been several reports of dangerous driving because of the partial road closure.”

Resident Rebecca Barnham said: “My son and daughter each have to cross this road twice a day.

“The incompetence with which these road works have been implemented has placed them and hundreds of others who use this junction at serious risk of injury or death.”

A Network Rail spokesman said the traffic management system had been amended to include signs and pedestrian signals.

He said: “The new arrangements are now working effectively.”