Lucknow, Jan 21: Senior Samajwadi Party (SP) leader and former minister in the state government Ambika Chowdhary on Saturday switched allegiance to the Bahujan Samaj Party (BSP).He joined the party in the presence of BSP chief Mayawati at the party headquarters here. Accusing Chief Minister Akhilesh Yadav of slighting his ageing father Mulayam Singh Yadav, Chowdhary said: "It was most unfortunate and had left him heart broken.""I will now contribute to the BSP's social engineering movement and help the party in the state assembly elections," he said. Ambika Chowdhary was a close aide of Mulayam Singh and his brother Shivpal Singh Yadav and was not liked by Akhilesh.Mayawati welcomed the SP veteran and assured that his honour and respect will be maintained in the BSP. He was also given a ticket from his traditional seat in Ballia. Chowdhary was with the SP for 25-long years.