The daughter of one of India's wealthiest men is embroiled in a fight over money with her estranged husband in a London divorce court.

Ankul Daga wants Aparna Bangur, daughter of billionaire businessman KK Bangur, to hand over a lump sum of £2.5 million following the breakdown of their relationship.

Ms Bangur is disputing his claim.

A judge began overseeing a trial at a public hearing in the Family Division of the High Court in London on Tuesday.

The hearing is due to end later this week and Mr Justice Holman is expected to produce a ruling in the near future.

A profile on says Krishna Kumar Bangur, chairman of Graphite India, is worth about £1.3 billion.

The judge has heard that Mr Daga lives in London.

Mr Justice Holman raised concern about the amount of lawyers' bills the pair had run up.

He said Mr Daga and Ms Bangur had spent more than £1 million between them.

"It really does give one pause for thought," he said. "What are we doing?"

Mr Justice Holman paused for thought when a Ankul Daga - a jain - began to swear an oath on a Christian Bible before giving evidence at a trial.

Mr Holman questioned whether Ankul Daga's oath would be correct.

The judge checked on the nature of Mr Daga's religious beliefs and whether he was aware what he was being asked to swear on.

Mr Daga said he was, explained the nature of Jainism and said he was happy to swear on a Bible.

A BBC online guide to religions says Jainism is an "ancient religion from India that teaches that the way to liberation and bliss is to live lives of harmlessness and renunciation".