The first trial of a LIBOR trader has ended with Mr Tom Hayes (see BBC 3rd August) being convicted on 8 counts of conspiracy to defraud. The trial judge, Cooke J, sentenced Hayes to a total of 14 years imprisonment. The sentencing remarks are available via the public Judiciary website. The activities of Hayes concerned LIBOR rates set for the YEN (¥ ). Cooke J said that the case had shown the "absence of integrity which ought to characterise banking."
Although the learned judge does not use the word deterrence, it seems that there is a deterrent element in the sentence. At para. 12 of his remarks, Cooke J said: "The conduct here must be marked out as dishonest and wrong and a message sent to the world of banking accordingly." Whether deterrent sentencing is entirely justifiable is an interesting question - see the article by Edward Woollard in The Guardian 24th January 2011. A further point (para 9) made by the judge was that it was no excuse that others were doing the same thing. That is a general principle. For instance, it is no excuse to speeding on the roads to say that other drivers were also doing it ! Regarding the sentence see the article by Joshua Rozenberg - The Guardian 4th August (Link added later on 4/8/15)
The Serious Fraud Office (SFO) was the prosecuting authority. See their statement - issued after the conviction of Mr Hayes - 3rd August - First LIBOR defendant on trial found guilty Charges against others have yet to come to trial and reporting restrictions apply to their cases.
As the law stood at the time of the offences committed by Mr Hayes, the most likely avenue for the prosecution of individuals was the use of the common law offence of conspiracy to defraud - discussed at Law and Lawyers - Can criminal law nail the LIBOR bankers? This offence was deliberately retained when the Criminal Law Act 1977 was enacted. Sentencing for conspiracy to defraud was considered by the Court of Appeal (Criminal Division) in R v Kallakis and Williams  EWCA Crim 709.
The Financial Services Act 2012 came into effect on 1 April 2013, making the administration of LIBOR a regulated activity overseen by the Financial Conduct Authority. The Act, which was not retrospective, made knowingly or deliberately making false or misleading statements in relation to benchmark-setting a criminal offence.
Proceeds of Crime proceedings against Hayes will take place later. The SFO has a Proceeds of Crime Division and some substantial orders have been obtained - e.g. Kallakis and Williams.
Other links concerning LIBOR:
Treasury Committee Report 18th August 2012 and the response of the Financial Services Authority 21st February 2013
Wheatley Review of LIBOR- September 2012 - (92 pp pdf)
Law and Lawyers 29th June 2012 - Financial penalty imposed on Barclays
Law and Lawyers - 3rd July 2012 - Heads begin to roll ~ Barclays ~ LIBOR aftermath
Bench-mark setting principles in the EU