Scope for Coercive Manipulation

Plea bargaining is criticized, particularly outside the United States, on the grounds that its close relationship with rewards, threats and coercion potentially endangers the correct legal outcome. Coercive plea bargaining has been criticized on the grounds that it infringes an individual's rights under Article 8 of the European Convention on Human Rights, incorporated in the UK's Human Rights Act 1998.
Author Martin Yant discusses the use of coercion in plea bargaining:
Even when the charges are more serious, prosecutors often can still bluff defense attorneys and their clients into pleading guilty to a lesser offense. As a result, people who might have been acquitted because of lack of evidence, but also who are in fact truly innocent, will often plead guilty to the charge. Why? In a word, fear. And the more numerous and serious the charges, studies have shown, the greater the fear. That explains why prosecutors sometimes seem to file every charge imaginable against defendants.
This tactic is prohibited in some other countries—for example in the United Kingdom the prosecutor's code states:
Prosecutors should never go ahead with more charges than are necessary just to encourage a defendant to plead guilty to a few. In the same way, they should never go ahead with a more serious charge just to encourage a defendant to plead guilty to a less serious one.
although it adds that in some kinds of complex cases such as major fraud trials:
The over-riding duty of the prosecutor is ... to see that justice is done. The procedures must command public and judicial confidence. Many defendants in serious and complex fraud cases are represented by solicitors experienced in commercial litigation, including negotiation. This means that the defendant is usually protected from being put under improper pressure to plead. The main danger to be guarded against in these cases is that the prosecutor is persuaded to agree to a plea or a basis that is not in the public interest and interests of justice because it does not adequately reflect the seriousness of the offending ... Any plea agreement must reflect the seriousness and extent of the offending and give the court adequate sentencing powers. It must consider the impact of an agreement on victims and also the wider public, whilst respecting the rights of defendants
John H. Langbein argues that the modern American system of plea bargaining is comparable to the medieval European system of torture:
There is, of course, a difference between having your limbs crushed if you refuse to confess, or suffering some extra years of imprisonment if you refuse to confess, but the difference is of degree,