BBC Democracy Live - Home Affairs Committee 13 January 2013 Last updated at 19:56 Help The Home Affairs Committee is taking evidence on the work of the National Crime Agency and the work of the home secretary. The first part of the sitting is focusing on the work of the National Crime Agency (NCA), with evidence from the agency's head, Keith Bristow. The NCA is a crime-fighting law enforcement agency responsible for leading the UK's efforts to cut serious crime. It has replaced the Serious Organised Crime Agency in a bid to achieve a more co-ordinated approach to fighting crime. Police forces in the UK have territorial responsibility for fighting crime. But the NCA has a strategic role in looking at the bigger picture of crime in the UK, at how it operates and how it can be disrupted. Modern crime is international and cuts across borders and the NCA seeks to bring together intelligence from at home and abroad to understand the international nature of how these groups work and how they can be stops. Home Secretary Theresa May has said that the NCA, which came in to force this month, will "relentlessly pursue" those involved in serious crime. The second part of the sitting will focus on the work of the home secretary, with evidence from Theresa May.