Mr Drewe, said to take an "intellectual delight in fooling people", is alleged to have organised a complex 10-year modern art fraud that earned him a great deal of money.
Southwark Crown Court was told earlier this week that Drewe, 50, created histories for non-existent works by artists including Marc Chagall, Graham Sutherland and Ben Nicholson, then paid a struggling painter to create them.
Judge Geoffrey Rivlin said: "Drewe has decided to dispense with the services of his entire legal team and conduct the case on his own. That is something he is fully entitled in law to do.
"I have been most anxious to be sure in my own mind that Drewe fully understands the ramifications, problems and possible difficulties of him conducting the case on his own."
While Drewe has dispensed with the services of Anthony Glass QC, he may occasionally be assisted by a legal adviser "if from time to time it becomes apparent he is not au fait with all the principles of criminal procedure and criminal evidence," said Judge Rivlin.
Drewe, from Reigate, Surrey, is said to have altered the archives of leading museums and galleries, including the Tate, where he created the histories for non-existent paintings. He also wrote to the families of some of the artists for more information.
When the hearing continued, John Bevan QC, for the prosecution, told the court that one dealer, who was sold a fake De Stahl by Drewe, was given four sketches, allegedly by Graham Sutherland, as compensation. It transpired that the Sutherlands were also fakes.
Mr Bevan said Drewe invented a bogus history for the Sutherlands to convince Whitford Fine Arts in London that they were genuine. He said Drewe had told the gallery that the sketches were rough drafts for the 70ft tapestry of Christ that Sutherland designed for Coventry Cathedral.
Drewe said that the sketches had been sold in 1976 by an Oxford priory and were now being sold by two private collectors. He also created a bogus catalogue to show that they had been part of a Sutherland exhibition held in 1967.
Drewe and Daniel Stoakes, 52, of Exeter, Devon, deny conspiring with John Myatt and others to defraud between January 1986 and April 1996. Drewe also denies charges of forgery, theft, and false accounting. The jury has been told that Myatt, 53, from Stafford, has admitted his involvement.
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