
Abhisit is scheduled to visit the United Kingdom to deliver the speech at the college tomorrow.
Thepthai Senpong, personal spokesman to Abhisit, denied that Oxford had called off the PM's speech, saying the government was aware of the move by Lee Jones, a research fellow and teacher on international politics.
Jones is linked with Dr Giles (Ji) Ungphakorn who fled to Britain after being charged in January with lese majeste for writing a book about the country's military coup in 2006.
Thepthai said Giles and Jones had joined forces to discredit Abhisit, but the PM would talk with Giles if he met him in Britain.
Prompong said Jones wrote to the university's management to claim that the Abhisit administration came to power with the help of "street politicians" who were rewarded with ministerial posts, and with the support of a splinter group led by Newin Chidchob.
He repeated the charge on his website. (Jones' letter)
Prompong quoted Jones as saying, "St John's may feel proud to have one of its alumni serving as Thailand's prime minister, but it can only embarrass itself by inviting such a figure to speak on the subject of 'democracy'.
In reality there is neither freedom of speech nor academic freedom nor democracy in Thailand today."
Prompong said he believed Jones's opinion would affect foreign investors' confidence in the country's democracy.
"The foreigners are confused now because Abhisit says he supports a sufficiency economy but he manages the country's budget using populist policies,'' Prompong said.