A new body to tackle some of the UK's most serious crimes has been launched.
Labelled the "British FBI", the National Crime Agency will "relentlessly pursue" organised criminals, the home secretary said.
Theresa May told the BBC it would focus on organised, economic and cyber crime, border policing and child protection.
It will replace a number of existing bodies but will have significantly less funding. Labour has called the move a "rebranding exercise".
It is the third time since 1998 that an organised crime body has been set up.
The National Crime Squad was set up 15 years ago, only to be replaced eight years later by Soca - which is now being scrapped.'Crime is falling'
The NCA will work with each of the regional police forces in the UK and similar organisations abroad.
The agency will have 4,500 officers and aims to adopt a more visible, joined-up approach than was previously the case.
The Serious Organised Crime Agency was much-maligned and is often said to have failed in its early days to make its mark. The National Crime Agency has to build its reputation as a formidable crime-fighter from day one.
But this is the third attempt to create a British FBI in 15 years. There is no new money. Some of its officers in their new black NCA jackets told me they'll be doing the same job they've always done.
So what's different this time?
The top cops at the NCA stress it will lead the national fight against crime, not simply sit alongside existing policing operations. They talk about the way intelligence from lots of sources will be combined for the first time and new powers will be used to task police forces to act. NCA specials, non-police officers with specialist skills, will be recruited from the private sector.
But one aspiration stands out. The NCA promises to be much more transparent than Soca - an organisation that didn't even put its name on its buildings.
The new agency will trumpet its successes, and fight for its reputation. Which might mean it has a better one.
Its head, Keith Bristow, warned criminals to expect "continuous disruption", including the confiscation of their assets.
"We are going to make a difference the public will see," he told the BBC, adding the "British FBI" label was "reasonable shorthand" for the new body.
The NCA has significant powers to compel police forces in England and Wales to provide assistance and carry out policing operations.
Mrs May told BBC One's Andrew Marr Show on Sunday that the new agency was "designed to be a relentless crime-fighting body which will relentlessly pursue organised criminals".
The home secretary said: "Crime is falling in this country, but we can't be complacent. And particularly on organised crime, I don't think the last government put enough emphasis on this."'Not strong enough'
But shadow policing minister David Hanson said the NCA "doesn't match the government's hype".
"Most of the NCA is just the rebranding of existing organisations such as the Serious Organised Crime Agency, but with a substantial 20% cut imposed by the Home Office on their overall budget," he said.
Mr Hanson added: "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.
"It is right to have stronger national action on organised crime with the NCA, on child exploitation and on intelligence - but the government has to support this effort and not simply use this as a rebranding exercise to hide substantial policing cuts."
However, Mrs May told the BBC she was satisfied that the NCA was "going to be well-resourced".
She said the government had already shown it was "possible to keep up that relentless fight against crime" with less money.
Keith Vaz, the chairman of the influential Home Affairs Select Committee said: "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."
Each police force in the UK has territorial responsibility for its particular area. Crimes that are carried out across more than one county or area usually involve officers from both areas.
The new body will have a strategic role in which it will attempt to look at the bigger picture of organised crime in the UK, how it operates and how it can be disrupted.
The NCA will answer directly to the home secretary and will have the same powers in Scotland as it does in England and Wales.
The situation will be different in Northern Ireland, where the agency will carry out its border and customs functions, but not other crime-fighting roles.