LONDON Shares in British-listed energy companies Centrica (CNA.L) and SSE (SSE.L) fell over 3 percent on Wednesday after opposition leader Ed Miliband said he would freeze energy prices if elected in 2015.
Though likely to be popular with voters, who have been hit in recent years by rising energy costs, the plan has placed Labour on a collision course with the energy companies.
The plan to impose a cap on business and consumer energy bills until January 2017 could cost the companies 4.5 billion pounds ($7.2 billion).
Shares in Centrica were down 3.8 percent, however about a third of that fall was due to the stock trading without entitlement to the latest dividend payout on Wednesday, which took 4.9 pence off the share price. <.L/XD>
Shares in SSE were down 3.4 percent.
Centrica said in response that if costs were to rise at the same time, the plans could make it economically unviable for suppliers to operate.
"The impact of such a policy would be damaging for the country's long term prosperity and for our customers," the firm said in a statement.
(Reporting By Christine Murray; editing by Kate Holton)