Samajwadi Party leader Ambika Chaudhary on Saturday joined the Bahujan Samaj Party in the presence of BSP Chief Mayawati. "I have resigned from all posts of SP and I'm joining the BSP with full dedication. I'm thankful to Behenji for including me in her party," Ambika said. He added that he was disappointed over Akhilesh Yadav's behaviour towards Mulayam Yadav.