The court recently rejected the bail pleas of Sudheendra Kulkarni and other BJP MPs - Faggan Singh Kulaste and Mahabir Singh Bhagora.
Many claim that Kulkarni has become the scapegoat over cash-for-votes scam which had rocked the Parliament ahead of the trust vote over Indo-US nuclear deal in 2008.
Kulkarni, the one time right hand of senior BJP leader LK Advani, appeared before a Delhi court seeking interim bail but was denied and sent to judicial custody.
Before his arrest, Kulkarni had stated, "I was only a whistle blower and my purpose was to expose the rampant corruption."
"There is no reason to deny interim bail to a person whose regular bail is pending (in the court) and who was not arrested during the investigation," hoped Kulkarni.
Amar Singh was granted bail on humanitarian grounds, said reports. The Delhi police had earlier accepted the medical reports submitted by AIIMS, where Singh is undergoing treatment currently.
Putting conditions along with a surety of Rs 50 lakh and personal bond of Rs 50 lakh, the former Samajwadi Party leader has been ordered not to travel abroad or even out of the Capital.