New Scotland Yard has been sold to Middle Eastern investors, Adu Dhabi Financial Group, for £370m.
The Adu Dhabi-based financiers beat 11 competitors from across the world to secure the deal, which was £120m above the asking price.
The iconic 1960s building will be demolished to make way into a new luxury residential and commercial development, reaching a height of 70m (230ft), with views of Westminster Abbey, Buckingham Palace, the Houses of Parliament and the London Eye.
The Met Police said the proceeds from the sale of the Westminster property will be go into frontline policing at a time when police budgets throughout the UK were under considerable pressure.
Met Commissioner, Sir Bernard Hogan-Howe said the force were expected to make up £1.4bn by the end of the next spending review, including some £600m by 2015/16.
"This is equivalent to a third of the Met's original budget so this money is absolutely vital to us," he said.
"It will allow us to reinvest in our remaining estate and in the technology needed to support our officers as they fight crime and support victims. It is only with this kind of intelligent investment that we will be able to do more with less."
Mayor of London Boris Johnson welcomed the deal to help increase officers on London's streets in the fight against crime.
He said: "The Met Police has a unique place in history and they need a home fit for the future, but police budgets are under real pressure. The sale of this under-used and outdated building means we can now not only protect that rich heritage, but also fund the new HQ and kit out bobbies with the latest mobile technology to secure the future of the force.
"This landmark deal allows us to preserve the past whilst giving today's Met a vital cash boost so our officers can go on keeping London safe."
The Met Police will now be moving to a £58m building along the Embankment, which is set to save the force over £6m a year in running costs. It has been located at the Westminster property since 1967.
Some cash from the sale will also be used to set up a museum to house unique police artefacts and policing memorabilia, which dates back to the formation of the Met Police in 1829.