NEW DELHI: A group of banks asked the Supreme Court on Tuesday to restrain the founder of Kingfisher Airlines, liquor baron Vijay Mallya, from leaving the country because of the hefty debt the now defunct company owes, two lawyers said. The creditors, led by the State Bank of India, have stepped up efforts to recover the debt — $1 billion as of January-end, 2014 — after Mallya last month resigned as chairman of spirits maker United Spirits, a unit of Diageo Plc. Mallya also said he would spend more time in England to be closer to his children. On Monday, a court blocked a $75 million settlement Mallya agreed with Diageo Plc at the request of the banks. Kingfisher, once India’s second-biggest airline, stopped flying more than three years ago.