Death row prisoners in the Caribbean may have their cases reviewed after Trinidad's mandatory death sentence for murder was ruled unconstitutional.
Trinidad has 86 death-row inmates
The London Privy Council rulings on two death penalty appeals will allow the island state's judges to reserve the sentence for the most serious murders.
Lawyers say Trinidad's 86 death row inmates will have to be re-sentenced.
Hundreds more in the Bahamas, Jamaica and Barbados have similar challenges before the Privy Council.
Convicted murderers Balkissoon Roodal and Haroon
Khan appealed to the Privy Council, the "appeal court of last resort" for many former British colonies, saying Trinidad and Tobago's laws
One law states murderers "shall suffer death" while another says capital punishment should be the
maximum penalty but not mandatory, according to British defence lawyers working on an unpaid basis.
Privy Council Judicial Committee
Founded in 1833
Deals with a dozen capital cases a year
Also acts as final civil appeal court for New Zealand, Mauritius, Tuvalu and Bermuda
Has power to overrule judges in Isle of Man and Channel Islands
Deals with appeals against General Medical Council and other professional bodies
Handles constitutional appeals regarding laws created by Scottish Parliament and Welsh Assembly
The council ruled murder cases were too varied to carry a mandatory sentence.
It also noted the possibility of executing
someone who had been falsely convicted.
The court also ruled Trinidad and Tobago had been party to the American Convention on Human Rights, barring mandatory death sentences, at the time of at least one of
Roodal has been on death row since July 1999 when he was sentenced to hang for shooting a man in an argument about the theft of marijuana plants.
His appeal was dismissed by the Trinidad and Tobago appeal court in February 2000.
Lords Steyn, Bingham and Walker, sitting in London, decided the mandatory death sentence was inconsistent with the international obligations of Trinidad and Tobago and unconstitutional.
Lords Millett and Rodger dissented.
Lord Steyn said according to the constitution the protection of "guaranteed fundamental rights" was the responsibility of the judiciary and not the parliament.
Only a minority of convicted murderers in Trinidad and Tobago were prosecuted on the basis of an intent to kill as the law required only an intent to cause really serious bodily injury, he added.
Saul Lehrfreund, a human rights lawyer at the London solicitors Simons Muirhead & Burton, who represented Mr Roodal, said the ruling would mean "a completely new set of procedures restricting the imposition of the death penalty in the first instance".
"It will also have significant implications in Jamaica, the Bahamas and Barbados, where the constitutionality of the mandatory death penalty will have to be decided, affecting at least 200 men and women on death row," he added.
In July 2002 the 15 members of the Caribbean Community (Caricom) applied for a $100m (£62m) loan to set up a Caribbean Court of Justice (CCJ) to replace the Privy Council.
A Caricom spokeswoman told BBC News Online a building had been earmarked in the Trinidadian capital Port of Spain
But the scheduled opening of the court
this month has been delayed until next year.
Caribbean leaders say the court will rid them of one of the
last vestiges of colonialism.
A spokesman for Jamaica's attorney general said the Privy Council was "out of step" with public opinion in the Caribbean.
But critics say the CCJ will be a "hanging court" with judges appointed by governments keen to clear their death rows.