Police are investigating allegations of protection rackets, violent intimidation, drug dealing and the involvement of illegal immigrants.
At stake are huge profits. On a good day a hot dog stall can take more than pounds 1,000 selling over-priced, low-quality food and drink.
In the latest outbreak of violence last week, hot dog sellers wielding iron bars and sticks clashed in the shadow of Buckingham Palace. Two unemployed Albanian men in their twenties were arrested on Monday, following the disturbance in Stafford Place, 100 yards from the Palace. One man was taken to hospital with serious head injuries and a hot dog cart was trashed.
There have been many violent incidents this year involving rival gangs of street traders selling hot dogs, burgers, roasted chestnuts and ice cream, said Inspector Ron Cook of the Royal Parks Constabulary. He believes the Albanians were casual employees working for West End criminals who control the trade. "There is massive gang involvement," he said. "Serious violence to control the best pitches is commonplace."
Other criminals have targeted vendors working busy tourist sites and demanded "protection" money. Earlier this year an East London man was jailed for demanding money with menaces from ice cream sellers at the Tower of London.
In the last year the illegal food traders have decamped to the Royal parks - St James's, Regent's Park, Kensington Gardens and Hyde Park - to escape tough new regulations by Westminster City Council, enabling town hall officials to seize and destroy the trolleys of persistent offenders.
"Westminster wants to stamp out the problem," said a council spokesman. "The trolleys break numerous food safety laws, they are unhygienic and a grave health risk."
Concern is also growing that some hot dog stands are being used as cover for drug dealing. Two years ago a female vendor outside a West End theatre was revealed to be selling cocaine.
The council's policy has led to the destruction of 600 trolleys and two ice cream vans. Eighty trolleys went to the crusher last week alone, and a task force of police, environmental health experts and council officers is planning a Christmas offensive against illegal traders.
Insp Cook said: "When Westminster clamped down on these vendors in 1996 they moved over onto our patch. We can't take their barrows. We just throw them out of the park and issue a court summons." Many traders accept the small fines as occupational hazards.
Chris Smith, Secretary of State for Culture, Media and Sport, is now looking for an MP to table a Private Members' Bill allowing Royal Parks officers to seize trolleys and vehicles.
Last summer an irate Prince Andrew went to the front gates of Buckingham Palace and demanded that the trolleys and ice cream vans move because the stench and noise was overpowering his apartments.
Tourists at Buckingham Palace were eating hot dogs last week after a vendor started frying greasy sausages near the gates. A stream of foreign sightseers watching the changing of the guard were paying pounds 2.50 for a dubious sausage in a roll to a young Albanian man, guarded by five friends.
Police believe the lucrative Palace patch is controlled by a man known as "Turkish Dave" whose henchmen hire and fire hot dog sellers. Turkish Dave operates from a fortified shop off Charing Cross Road, sending sellers to West End streets and the Royal Parks.
A business associate who gave his name as Hassan said the unregistered company rented trolleys to traders for pounds 40 a day. He denied they asserted any control over the pitches. He said Westminster Council's seizure policy was only having a "little" impact on the business. People using their trolleys had to pay a deposit of pounds 1,000 for the equipment which was forfeited if the trolley was taken by the council. He had heard of the Albanian violence but said Turkish Dave was not involved.
Police fear the turf war could spiral out of control as it did in Leicester in the early 1990s when rival hot dog barons clashed, involving several murders and disappearances, protection rackets and arson.
Glasgow was reminded of a similar long criminal feud last week, when Douglas Dewar, the Scottish Secretary, denied an appeal by Joseph Steele and Thomas "TC" Campbell who were sentenced to 20 years' imprisonment for the murder of six members of the Doyle family in 1984 in what became known as the "ice-cream war".