A US man accused of becoming an al-Qaida agent discussed bombing New York cinemas, Grand Central Terminal, Times Square and the Stock Exchange before settling on the city’s subways, a court heard today.

An American-born al-Qaida recruit has become one of the counter-terrorism world’s most valuable informants, giving investigators a rare look at al-Qaida’s day-to-day operations in a lawless region bordering Pakistan which US officials have struggled to infiltrate, investigators said.