India's Supreme Court has directed PM Manmohan Singh to explain his "alleged inaction" in failing to sanction the prosecution of a former minister.
Telecommunications Minister A Raja has resigned over allegations he undersold mobile phone licences worth billions of dollars. He denies the claims.
Opposition MP Subramanian Swamy says he wrote letters to Mr Singh in 2008 calling for Mr Raja's prosecution.
He says Mr Singh took more than a year to reply, which the government denies.
The Supreme Court has now directed Mr Singh to explain in writing his "alleged inaction and silence for 16 months" on Mr Swamy's plea.
In India, the prosecution of a cabinet minister has to be cleared by the prime minister.
BBC News
