The extradition of a British businessman has highlighted problems with the treaty between the UK and the United States which are not "readily curable", the Attorney General said on Tuesday.
Dominic Grieve QC said Britons were left uneasy when faced with the seemingly harsh and disproportionate sentences in the American justice system.
His comments come as retired British businessman Christopher Tappin, who faces up to 35 years in jail if convicted over arms dealing charges, will appear in a US court after losing his two-year battle against being sent to America last week.
Mr Grieve said: "I think there's a lack of public confidence in the US justice system, which is a rather wider issue and more complicated than the minutiae of the treaty agreement.
"There are perceptions in this country that the US criminal justice system can be harsh, its penal policy can be harsh, and its sentencing policy can appear disproportionate by European and British standards.
"There are aspects of it therefore which tend to make people uncertain and uneasy, and I'm not sure that that's readily curable."
Mr Grieve admitted the UK's extradition laws were not ideal, but said: "In a world where we wish to see crime successfully combated, having a system by which to facilitate transfer to countries which meet the necessary criteria of fairness so as to curb crime is absolutely indispensable."
He added: "Perhaps we are where we are today because we rushed things in 2003."
Asked about Tappin, he said: "Any circumstances in which a person of Mr Tappin's age is going to be extradited to a country, a very long way from home, separated from his family, to be involved in the criminal justice system with clearly an uncertain outcome from his point of view... is going to be stressful and distressing."
He said there was "rather considerable scrutiny" before Tappin was extradited, but admitted the circumstances caused the public "disquiet".
"It may be linked to Mr Tappin's respectability... and his age, in contrast for example to an individual who may attract public opprobrium and be seen in one way or another as being rather undesirable."
Mr Grieve was giving evidence to MPs just minutes after Mrs Tappin, 62, of Orpington, Kent, broke down in tears as she described how her family felt "incredulity, frustration, heartrending sadness, despair and utter disbelief" as they faced a "wholly uncertain future".
In a written statement which she was unable to finish reading, Mrs Tappin went on: "At the heart of our despair is the fact that nobody was prepared to listen to Chris's defence before carting him off.
"They ticked the boxes but were deaf and blind to the possibility of injustice."
Mrs Tappin said she had still not been able to talk to her husband since he was extradited and he was being held in isolation, "locked up for 23 hours a day".
She said it was the "cruellest blow" when her husband lost his battle against extradition, saying he "was stunned and totally devastated when his appeal was rejected".
Mrs Tappin, who has chronic Churg-Strauss syndrome, was accompanied by her son, Neil, when she gave evidence to the Commons Home Affairs Select Committee for its review of extradition arrangements.
Just last week she tearfully accompanied her husband to Heathrow Airport, before he was handcuffed and seated between two US marshals on a plane to America.
Mr Tappin, the president of the Kent Golf Union, who is currently in custody, is due in court in El Paso, Texas, for a procedural hearing at 2.30pm local time (8.30pm GMT) on tuesday evening.
He is likely to be remanded in custody for three days when a bail hearing will take place, according to lawyers.
His MP, Tory Jo Johnson, and UK Independence Party leader Nigel Farage, who has known the businessman for nearly 40 years, have asked Home Secretary Theresa May to intervene to ensure the US authorities do not object to bail.
Tappin denies attempting to sell batteries for surface-to-air missiles which were to be shipped from the US to Tehran via the Netherlands.
Janis Sharp, the mother of computer hacker Gary McKinnon who is fighting extradition to the US, and David Bermingham, one of the NatWest Three bankers who spent 17 months in prison after being extradited to the US in 2006, were in the public gallery for today's hearing.
Prime Minister David Cameron's spokesman declined to discuss the Tappin case at a regular daily media briefing in Westminster, saying only: "That is a case that the Home Secretary has considered."
On the issue of the UK's extradition arrangements with the US, the spokesman noted that the Government is currently considering its response to the review conducted by former Court of Appeal judge Sir Scott Baker. The Baker report, published in October, found that the treaty "does not operate in an unbalanced manner".
"The Prime Minister has said we will consider that alongside the views of Parliament and that is what we are doing," said the PM's spokesman.
"Clearly he understands that there are strong views in Parliament and he was making the point that we will of course listen to those views."
Shami Chakrabarti, director of civil rights group Liberty, said: "No-one is saying that there shouldn't be effective co-operation between countries to bring suspects to justice.
"But how is it just that someone can be taken from his home, family and country without any evidence being probed in a local court?
"How is it just that UK judges retain no discretion whatsoever to find that someone would be better tried in this country?
"Mr Tappin's case demonstrates how Britain's extradition arrangements are in danger of becoming a tragic farce that undermines the reputations of our Government, our legal system and our allies."