A prisoner and his son have admitted conspiring to pass drugs through the Bullingdon Prison visitors centre only a week after a judge said the jail was rife with drugs.

Nicholas Lambrianou, 59, -- the brother of the Kray twins' feared henchman Tony -- and his son, also called Nicholas Lambrianou, 30, admitted trying to get cannabis into the Bicester jail.

At Oxford Crown Court yesterday, Judge Julian Hall warned the pair: "The guidelines on this are quite crisp -- people conspiring to deal into a prison generally end up in it."

The court heard how Lambrianou senior, who is already serving an eight-year sentence for dealing heroin in Banbury, arranged with his son for a supply of cannabis to be brought to the prison.

They both pleaded guilty to one count of conspiracy to supply a class C drug between March and May last year, but on the basis that it was for personal use, not for supply to other prisoners.

Lambrianou junior, a heating engineer, had a similar previous charge against his name from 1999, again at Bullingdon Prison.

Then he was seen dropping a package into the coffee cup of a man he was visiting. The man swallowed the contents. When confronted, Lambrianou admitted it was cannabis.

Last week, drug dealer Simon Day avoided a prison sentence when another judge agreed that it would be too easy for the man, who was also an addict, to get drugs while in prison.

Lambrianou senior, of The Fairway, Banbury, and his son, of Pellerin Road, London, were ordered to return on May 27 for sentencing.

Lambrianou junior, who has a young son, was given bail, but Judge Hall said: "Don't take this as any indication -- just use it to sort out your affairs, as it is almost certain you will be going to prison."

His father was returned to prison.