The two men who shot and stabbed businessman Mohammed Raja to death have been told by a judge they will serve at least 20 years behind bars.

David Croke, 62, of East Moulsecoomb, Brighton, and Robert Knapp, 58, of Abbeyfeale, County Limerick, Eire, were both convicted at the Old Bailey in July 2002 of the murder of Mr Raja.

They were each jailed for life, and Mr Justice Newman ruled that their tariffs should be set at a minimum of 20 years.

Taking into account the time the pair have already spent behind bars, they will not be considered for parole until 2021.

Mr Raja, 62, was shot at point-blank range when he opened the door to Croke and Knapp at his home in Sutton, Surrey, in 1999.

At trial, it was the Crown's case that the pair had been hired by multi-millionaire Nicholas Hoogstraten, who was alleged to have wanted to teach his former business associate "a lesson".

Mr Hoogstraten was convicted of manslaughter but later had his conviction quashed at the Court of Appeal and was acquitted at the start of his Old Bailey retrial.

Mr Justice Newman said he had at first recommended Knapp and Croke - both of whom had been released from prison shortly before they killed Mr Raja - serve at least 25 years behind bars.

After reconsidering the case, he said 20 years was more appropriate but underlined the murder was part of a "professional criminal enterprise"

carried out for "reward or favours". He added that he had thought about imposing a "whole life tariff" on the pair but concluded he couldn't be sure that the original plan had been to kill Mr Raja.

That was because, said Mr Justice Newman, the jury had acquitted Mr Hoogstraten of murder and Mr Raja had armed himself with a knife when Croke and Knapp arrived and his killing could have resulted from his efforts to defend himself. When Mr Raja opened the door on Croke and Knapp, he was stabbed five times and a shot was fired which struck the ceiling in the hall.

The gunman - the Crown could not be sure whether Croke or Knapp pulled the trigger - then reloaded and shot Mr Raja in the head from a range of less than a foot.

Even after the duo have served their 20-year tariffs, they will only be released if they can persuade the Parole Board they pose no public danger.

Once they regain their freedom, they will remain on "life licence" for the rest of their days, subject to recall to prison if they offend again.