Britain's Labour party will freeze gas and electricity bills until 2017 and force reform of the British utility market if it wins power in the May 2015 election, party leader Ed Miliband said today.

Miliband told party activists at the annual Labour conference in the English seaside resort of Brighton he would impose a cap on business and consumer energy bills until January 2017, forcing suppliers to bear what a Labour party source said could cost 4.5 billion pounds ($7.2 billion).

The majority of polls show Labour is on course to win the 2015 election, but its lead over David Cameron's Conservative party has narrowed in recent months.

"The system is broken and we're going to fix it," he said. "If we win that election in 2015 the next Labour government will freeze gas and electricity prices until the start of 2017. Your bills will not rise. It will benefit millions of families and millions of businesses."

Britain is Europe's largest gas consumer due to the high amount of heaters fired by gas and is one of the top three traded electricity markets in Europe.

The retail market is dominated by six major utilities which cover around 99 percent of the market. They are: Centrica , SSE, Scottish Power, EDF Energy , RWE npower and E.ON.