The Bahujan Samaj Party on Thursday filed a petition before assembly Speaker Kesrinath Tripathi, seeking disqualification of 13 of its legislators who had extended support to Uttar Pradesh Chief Minister Mulayam Singh Yadav.

The petition, filed by BSP legislature party leader Swami Prasad Maurya, appealed to Tripathi that a decision on the fate of the MLAs be taken before September 8, when Yadav is scheduled to seek a confidence vote in the House.

"They should be debarred from taking part in voting.

"By their conduct, these MLAs have proved that they no longer want to be part of the BSP and, therefore, they should be disqualified," the petition said.

Later, Maurya said the BSP legislature party had sought copies of the letters in support of Yadav given by a section of party legislators to Governor Vishnukant Shastri.

"We wrote twice to the governor's secretariat but we were asked to take the letters from the speaker," he said.

"We were told that the governor could hand over copy of the letters only on the directives of a court."

In the letter, the 13 legislators had urged the governor to invite Yadav to form the government.