Dubbed 'Britain's FBI', the NCA will tackle the country's most serious organised criminals at home and abroad, replacing SOCA.
Ten new alleged tax-dodgers have been added to the Government's most-wanted list.
Fifty years ago, they were involved in 'the crime of the century'. But what happened when the law caught up with the great train robbers?
Five people have been arrested as part of a crackdown on suspected identity fraudsters in the first major operation led by the new National Crime Agency.
Officers carried out early morning raids today in Liverpool, Warrington, Bromley, south east London, Brentwood, Essex, and Troon.
The arrested individuals are suspected of fraudulently applying for genuine passports or driving licences using hijacked or stolen identities.
The arrests followed months of planning involving major agencies such as the Metropolitan Police Service, National Fraud Intelligence Bureau, HM Passport office and the DVLA.
The National Crime Agency to tackle the country's most serious organised crimes has been launched today.
Its officers recently carried out a series of training exercises
Keith Vaz, the chairman of the Home Affairs Select Committee has questioned the budget of the National Crime Agency and whether it is large enough to cover its new remit.
He told the BBC: "The organisations going into the NCA have a combined budget of £812m, yet the new agency will only have £473.9m next year.
"The Home Office needs to account for where this money has gone."
Shadow policing minister David Hanson says The National Crime Agency "doesn't match the Government's hype".
He added: "It is welcome the NCA has finally arrived after three years of delay and we support strengthening work on organised crime and the hard work of Keith Bristow and his team.
"But most of the NCA is just the rebranding of existing organisations such as the Serious Organised Crime Agency, but with a substantial 20 percent cut imposed by the Home Office in their overall budget.
"The new organisation is not strong enough to deal with the exponential growth of economic and online crime. It will simply absorb the existing National Cyber Crime but with fewer resources.
"And due to Government mishandling it won't be able to operate in Northern Ireland leaving a serious operational gap compared to the Serious Organised Crime Agency that it replaced."
Director General of the NCA, former Warwickshire Police Chief Constable Keith Bristow, says unlike Soca, the new agency would not operate as a covert organisation and wants to be recognised by the public.
Some of its officers will wear jackets and caps emblazoned with NCA when on operations.
"We're going to be visible," he said. "We want the public to know who we are, what we do, what we're delivering, to understand the serious and organised crime threat that effects every neighbourhood and every citizen throughout the UK."
He added: "Frankly, we want the criminals to know who we are, because we want them to fear our attention."
NCA Director General Keith Bristow says the new agency will lead the UK's fight to cut serious and organised crime.
- More than 4,000 NCA officers will tackle crime under four commands: organised crime, economic crime, border policing and child exploitation and online protection, alongside a National Cyber Crime Unit.
- The NCA has an annual budget of £463 million for resources and £31 million for capital.
- The NCA will run the country's first national intelligence hub, place investigators at UK ports to tackle border crime such as human trafficking and will track down child-sex abusers online.
- It will also place around 120 officers overseas in 40 different countries.
The head of the newly formed National Crime Agency, dubbed 'Britain's FBI', has warned the Mr Bigs of the underworld there will be "no one beyond the reach" of the new agency.
The agency, which goes live today, has a budget of nearly half-a-billion pounds a year and will lead the fight against the estimated 37,000 criminals involved in serious and organised crime that hits the UK.
More than 4,000 NCA officers will tackle crime under four commands, organised crime, economic crime, border policing and child exploitation and online protection, alongside a National Cyber Crime Unit.
NCA director general Keith Bristow said: "To be clear, there will be no one beyond the reach of law enforcement or beyond the reach of the NCA. Those people involved in the most horrible activities can expect the most comprehensive and robust response."
These dramatic CCTV images show the moment a petrol station security guard was held up at rifle-point by a masked man in Ilminster, Somerset.
The guard was confronted as he left the shop and threw a security box full of money at the robber, who then fled in a stolen Ford Fiesta with an accomplice.
The car was dumped less than a mile away, when the suspects are thought to have escaped in a second vehicle.
Avon and Somerset police are appealing for more information regarding the incident, which took place on the morning of Monday 23 September.
With Amanda Knox today revealing she will not go back to Italy to face re-trial over the Meredith Kercher murder case, here is a summary of the key events since the 21-year-old student from Surrey was found dead:
- 2 November 2007: Kercher's body found in her apartment in Perugia
- 6 November 2007: Knox and Raffaele Sollecito arrested
- 6 December 2007: Ivory coast national Rudy Guede extradited from Germany and arrested in Italy
- 28 October 2008: Guede convicted of murder and sexual assault, sentenced to 30 years
- 4 December 2009: Knox and Sollecito found guilty of murder and sexual assault, sentenced to 25 years
- 3 October 2011: Knox and Sollecito cleared of murder after four years in prison
- 12 September 2012: Sollecito pens book on Kercher's murder
- 26 March 2013: Knox and Sollecito ordered to face retrial
- 1 May 2013: Knox reveals desire to visit Kercher's grave in first TV interview
- 1 July 2013: Sollecito says he and Knox were "victims"
- 3 September 2013: Sollecito says he did not regret kissing Knox hours after Kercher's death
- 15 September 2013: Knox says she "won't go back to Italy for retrial"