NEW DELHI: India’s upper house of parliament has rejected Vijay Mallya’s resignation of his seat, saying a letter the embattled tycoon sent from Britain did not conform to “procedures” or carry an original signature.

The 60-year-old multimillionaire left India for Britain in March owing more than $1 billion in unpaid loans, and is under investigation by a parliamentary ethics committee.

India’s government has revoked his passport and asked Britain to deport him, but Mallya told the Financial Times last week he had no plans to leave Britain and wanted to reach a “reasonable” settlement with Indian banks.

On Monday he resigned from the Rajya Sabha, or upper house, saying in a letter to the chairman that he did not want his name to be “further dragged in the mud” and calling the accusations against him “false and baseless.”

But Rajya Sabha Chairman Hamid Ansari said late Tuesday that the letter was not valid.

“Hamid Ansari, chairman, Rajya Sabha, does not accept the resignation of Vijay Mallya,” Ansari’s aide, Gurdeep Singh Sappal, posted on Twitter.

“His resignation letter does not conform to prescribed procedures and does not bear signature in original.”