Murali to retire in 2007

On Sunday, Muralitharan overtook Courtney Walsh's record of 519 Test wickets against Zimbabwe last week.

ICC boss Malcolm Speed said: "The report proves the degree of straightening is well outside the ICC's specified levels of tolerance.

"Sri Lanka Cricket has instructed Mr Muralitharan not to bowl the delivery."

It appears the spinner will shelve the doosra - for now.

"People have questioned me about it. I have done all the tests that are required and the reports have gone to the ICC," Murali told Colombo's Daily News.

"At the end of the day what matters is what the report, the expert, my cricket board and the ICC says."

Sri Lanka Cricket and the University of Western Australia, which produced the report declaring the doosra illegal, believe the levels of tolerance should be increased.

The ICC is well aware that the existing body of scientific knowledge in relation to spin bowlers would benefit from additional research Malcolm Speed

Speed added: "The authors of the report expressed their opinions about the current regulations governing the levels of tolerance used to assess a bowler's action.

"Sri Lanka Cricket has advised the ICC that it will be seeking to have these regulations changed at the earliest opportunity."

The report showed an initial straightening of Muralitharan's arm of around 14 degrees, which after some remedial work was reduced to 10 degrees.

This compares to an allowable level for spinners of five degrees under ICC regulations.

Speed reckoned most bowlers straighten their elbows a small amount under analysis, contrary to the original rule, and conceded the level of tolerance could be extended in future.

"The ICC is well aware that the existing body of scientific knowledge in relation to spin bowlers would benefit from additional research and has previously announced that it will undertake this work," he added.

"It will only be after this research is completed that the ICC will be in a position to know if there is a sufficiently strong fact-based argument to alter the levels of tolerance currently in place."

The issue is at the top of the agenda for a meeting of the ICC's cricket committee, headed by former India batsman Sunil Gavaskar, in Dubai on Thursday.