Sanjeev and Sadhana Prasad, 61 and 57, say they expended their savings on their son – paying for his training as a pilot and a lavish wedding – yet he has not given them a grandchild.

They are seeking $650,000 (£525,000) if no grandchild is produced within a year.

The case is being brought on the basis of “mental harassment”.

Mr Prasad said he spent $65,000 on his son’s pilot training in the US and had to support him for a further two years when he returned to India in 2007 and lost his job.

Shrey Sagar, 35, did ultimately get a job as a pilot. The parents had arranged his marriage to Shubhangi Sinha, now 31, in 2016 in the hope they would have a “grandchild to play with” in retirement.