The CMA has a range of powers including fines they can impose on firms.
“It’d be completely unacceptable for anyone to use this crisis, to rip people off,” Miliband said. “And we will fight people’s corner to stop that happening.”
However, whether the government took further steps to support households would depend on how long the conflict lasted, he added.
He emphasised that the chancellor had previously shown a “willingness to intervene”, a reference to moves in November’s Budget to ease energy bills, with additional money targeted at vulnerable households.
Fuel duty, which is currently frozen, is set to rise in September. That was now under review, Miliband confirmed.
Shadow transport secretary Richard Holden said Reeves “could cancel the fuel duty rise, she could cut the taxes piled on to energy, she could stop piling costs on to the price of fuel – but she isn’t doing anything because she doesn’t have the backbone”.
“A 5p-per-litre duty increase at the pump will hit commuters, families, and small businesses already under pressure from the cost of living and Labour’s tax hikes,” he added.
“The latest developments in the Middle East make it even more important that the chancellor thinks again,” Holden said.
