The ban could hit an economy still reeling from foot and mouth

The Lake District National Park Authority wants to introduce the speed limit from March 2005.

But campaigners against the move, including former sports minister Kate Hoey, say it will turn tourists away.

The campaigners, called Windermere Action Force, are submitting a report to national park bosses.

It claims a 10mph limit could result in the creation of dangerously large washes from powerboats using the lake.

The national park authority says the speed limit will make the lake a more tranquil place to visit.

But businesses say it will devastate the local economy, which is still recovering from the foot-and-mouth crisis of 2001.

The four busiest areas of the lake already have a 6mph limit, and from March 2005 there will be a 10mph limit on the rest of Windermere.

Ms Hoey said: "I think the national park authority is going to have to answer some very serious questions.

Kate Hoey has campaigned against the planned speed limit

"The government and the Department for the Environment, Food and Rural Affairs (Defra), the department that now has responsibility for this issue, will also have to look at this very carefully.

"I am quite convinced that when people who come to this with open eyes and not with a blinkered view, will realise that we have to find a way out."

Earlier this year Ms Hoey joined hundreds of campaigners to demonstrate against the planned 10mph limit.

If it goes ahead, the speed restriction will effectively mean the end of sports boats and activities such as water-skiing.

Ms Hoey said the authority should be able to devise a management plan dividing the lake into separate areas.

Ms Hoey became an opponent of the speed limit while she was sports minister, but she failed to persuade councillors and national park officials to abandon the plan.

The campaigners have asked for talks with the national park authority to see if Windermere can be managed to provide space for fast water sports.

But a report after a public inquiry concluded there was "no conceivable way" in which the lake could be managed to accommodate both large numbers of sports boats and other pursuits such as sailing and canoeing.

The national park authority says it has no intention of reversing its decision.