Congestion is already severe at peak times around the motorways towards the east of the city.

But plans for thousands of new homes and a new business park are expected to put increased pressure on congested roads.

The Highways Agency will release a study in the next few days showing the possible impact of new developments.

Excellent links

The Met Office and London Electricity are among several companies moving into the east of the city.

They are attracted by excellent links to the rest of the country by air, road and rail.

But members of the Exeter Business Forum are concerned that the city will not be able to cope with the influx unless urgent steps are taken.

Peter Lacey from the forum said: "If it's ignored, the consequences could be very significant.

"It certainly will curtail the development we've seen over the last few years, or at least its growth."

The building of 600 new homes has already been delayed because of the roads problem.

The Highways Agency cannot ban schemes going ahead but its advice must be taken seriously by planners.

Exeter City Council says it prides itself on having an impressive transport system and it is confident a solution will be found.