A new law targeting trade in stolen metal has come into force.
All scrap dealers and motor salvage operators in England and Wales must now apply for a licence from their local authority and keep records on who they buy from.
The Scrap Metal Dealers Act 2013 is aimed at thefts which have blighted the rail and power industries and seen churches targeted.
The act also extends a ban on cash payments to mobile collectors.
Trade body the British Metals Recycling Association (BMRA) has welcomed the changes.
The Association of Chief Police Officers (Acpo) set up a working group on metal thefts after estimating the illegal trade was costing the UK economy £770 million a year - it says such thefts are now falling.
Paul Crowther, deputy chief constable of British Transport Police and national lead on metal theft for ACPO, said: "We've all heard the stories about the impact on communities, businesses and individuals, and these new regulations and powers really provide us with the tools to crack down on metal theft.
"The problem has always been that people who turn up at a scrap metal yard are virtually untraceable once they trade the metal."
Councils will assess whether each licence applicant is a "suitable person" - including examining criminal convictions - and will have more powers to carry out inspections.
Dealers who have not registered by 1 December face prosecution with fines of up to £1,000, limits on trading hours and the possibility of being shut down.
BMRA director general Ian Hetherington described the new act as "a watershed moment for the industry. It's an opportunity to rid the industry of the Steptoe and Son stereotype once and for all."
The new rules require dealers to record the value of the metal purchased, as well as proof of the seller's identity and address, and keep the records for three years.
Gary Cooper, director of operations and engineering at the Association of Train Operating Companies, described the changes as "excellent progress in the fight against cable thieves, whose actions cause delays and disruption for thousands of our customers".
Traders can apply for a temporary licence before 15 October in order to continue working while councils process full applications.