Energy companies and airlines have been urged by chancellor George Osborne to pass on the benefits of falling oil and gas prices to customers.
The Treasury has begun an internal investigation into the behaviour of companies that depend on oil and gas.
The price of oil is about $50 a barrel, the lowest since the 2008 financial crisis, having dropped 50% over the past 12 months.
Brent crude, the global benchmark, was down $2.37 to $50.73 a barrel.
The chancellor told cabinet colleagues yesterday that families should feel the rewards of the drop in oil prices through cheaper bills and flights.
He added that businesses would be “watched like hawks” to see if they were reducing prices, the Times reported.
A Treasury spokesman hinted at unspecified further action if energy companies failed to pass on their reduced costs to customers. This could include referral to the Competition and Markets Authority.
A source pointed to supermarkets that have dropped fuel prices as evidence that cuts could be passed on to customers, calling for other industries to follow suit.
“So far it has worked with fuel prices,” the Treasury source said of the government pressure on companies to pass on their reduced costs. “Pump prices are coming down; we believe it can work with other industries.”
Petrol prices have dropped in line with oil prices after a delay of about two weeks.
On Twitter, Osborne said: “Vital this is passed on to families at petrol pumps, through utility bills and air fares.”
No 10 said the prime minister was “very keen” to see price falls passed on.