Scotland Yard has warned businesses in London to expect a Mumbai-style attack on the capital. In a briefing in the City of London ... a senior detective from SO15, the Metropolitan police counter-terrorism command, said: Mumbai is coming to London." The detective said companies should anticipate a shooting and hostage-taking raid "involving a small number of gunmen with handguns and improvised explosive devices". The warning - the bluntest issued by police - has underlined an assessment that a terrorist cell may be preparing an attack on London early next year. It was issued by the Met through its network of "security forums", which provide business leaders, local government and the emergency services with counter-terrorism advice. Officials now report an increase in "intelligence chatter" - communications captured by electronic eavesdropping agencies. One senior security adviser said the police warnings had intensified and become much more specific in the past fortnight. "Before, there has been speculation. Now we are getting what appears to be a definite plot to carry out a firearms attack on London," he said. Earlier this year, police, military and intelligence services held an exercise in Kent to see whether they could defeat a commando raid in London by terrorists.