It also follows new EU health and safety rules limiting noise levels from the traditional Scottish instrument.

Inspector Bruce Johnston of Lothian and Borders Police said: “These pipers are regarded as unlicensed trade and are technically buskers.

“Some of them are coming over from Glasgow, working in shifts and making £80 an hour, on which they don’t pay any tax,  so it amounts to quite a good illegal earner. There is somewhere in excess of 100 houses with windows looking out on to these areas and most of the complaints have come from residents.

“Some work on nightshifts, attend university and study at home, have small children or are very elderly.”

Pipers will be allowed to perform on Edinburgh’s streets during the annual Festival Fringe in August – if they pay a £50 performance fee for a 20-minute slot outside the Tron Kirk.

The contracts informed pipers that, under the Civic Government (Scotland) Act, 1982, they can be prosecuted and may also have their instruments seized.

City Centre Councillor David Beckett said he supported the police action. He added: “At the end of the day, we have to look after our residents first.”

Edinburgh-based piper Glyn Morris, 29, said: “There have been a number of buskers coming in from outside and piping up and down the Mile at all hours of the day.

“They have spoiled it for the rest of us, so I think the only way forward is licensing.”

Earlier this year, pipers warned EU bureaucrats in Brussels that noise limits would virtually outlaw the instrument.