The young Treasury minister was unable to answer hostile questions from Jeremy Paxman yesterday.

Disastrous Chloe Smith interview piles pressure on Cameron and Osborne

Disastrous Chloe Smith interview piles pressure on Cameron and Osborne

Chloe Smith's car-crash interview on Newsnight yesterday evening has dominated events in Westminster, with David Cameron and George Osborne left reeling by the response to their latest U-turn.

The junior Treasury minister endured an unceremonious interview with Jeremy Paxman in which she was subject to a barrage of questions about the government's decision to continue the freeze on fuel duty.

Tory backbencher Nadine Dorries tweeted that the chancellor was "a coward as well as arrogant" to send out Ms Smith for the Newsnight interview.

"Newsnight last night would have been a tough gig for a minister with years of experience – Chloe is a good egg and didn't deserve that," she wrote.

"The submarine chancellor sacrifices another minister whilst he slips under the surface…again."

Speaking during PMQs today, Labour leader Ed Miliband dwelled on the point.

"He claims to be proud of the way the fuel duty decision was made," Mr Miliband said.

"The chancellor hid away yesterday, refusing to defend the decision," he added, before reading out Ms Dorries' comments to the Commons.

Mr Cameron replied: "The leader of the opposition says the chancellor was hiding away. The chancellor was announcing the tax reduction from this despatch box.

"I know Westminster doesn't always get well reported but he [Miliband] was here when it happened."

After the session, the prime minister's spokesperson insisted it was standard procedure for the chancellor to announce a policy in the Commons and then send junior ministers to defend it in TV interviews.

But Ms Smith struggled to explain herself during the Newsnight appearance and appeared dangerously under-briefed.

She was repeatedly asked by Mr Paxman when she learned of the fuel duty U-turn, in scenes reminiscent of the infamous Michael Howard interview in which he was asked 12 times if he overruled a prison governor.

Questioned as to why she had recently said "it is not certain that cutting fuel duty would have a positive effect on families or businesses", Ms Smith could only reply: "It's important to do what you can to help households and businesses".

The minister's inability to answer the question, or even explain how the policy would be paid for, triggered a wave of critical responses to her performance, but the interview will be just as damaging to the chancellor.

Mr Osborne, who is dubbed 'the submarine' in Westminster for his ability to emerge for set-piece events but disappear at the first sign of trouble, is losing political credibility as his Budget falls apart in a series of U-turns.

With reports online that Tory MPs were still being told to brand Labour's demand for a fuel duty freeze "the worst kind of hypocrisy" at 12:30 BST yesterday, Ms Smith's inability to stick to a government line seems considerably more understandable.

Her humiliation on the BBC's flagship current affairs programme will be a symbol to Tory MPs that Mr Osborne's U-turns could easily damage their own standing.

Unfortunately for Ms Smith, who is just 30 years old, most senior Conservative MPs remain too irritated by her appointment to be sympathetic.