A multi-millionaire business owner made to pay his third wife a £73million divorce payout is still embroiled in a legal row that could see him give her another £17million.

Janie Martin was a 23-year-old employee 'on the shop floor of Rupert Martin's factory' when the pair got together in 1985.

Lighting business tycoon Mr Martin, now 69, was still with his second wife when they met, but the pair got married and stayed together for 29 years.

The couple, who have two grown up children, 'enjoyed a very high lifestyle,' with a £5million home in Somerset, a £10million ultra-modern residence in Hampshire and a £2.6million property on Chelsea's King's Road before they separated in 2015.

When they divorced in 2017 a judge ruled Mrs Martin should have £73million of his £220million fortune.

But now they are both back in court, with her demanding £17million extra and him calling for her original payout be cut by 'many tens of millions of pounds'.

Lighting business tycoon Rupert Martin (pictured outside London's Court of Appeal left) is embroiled in a legal row with his third wife Janie (pictured right) over his million-pound fortune

London's Court of Appeal heard Mr Martin, whose £220m Dorset-based lighting manufacturing business, Dextra Group PLC, has lucrative contracts with supermarket giants Tesco and Iceland, married Janie, his third bride, in 1989.

Judges were told Mr Martin spends £1million a year funding a motor racing team his 30-year-old son Alex drives for, and recently splashed out over £5million on an 860-acre shooting estate in Somerset.

The court was told the couple got together in 1985, when 'the wife was a worker on the shop floor of the husband's factory' and Mr Martin was still married to his second wife.

He got divorced in 1987 and married Janie, now 56, who had also been married once before she got together with her then boss.

For 29 years before they split, they enjoyed a vast 'personal fortune' and were 'able to buy a number of properties of exceptional quality in London, Hampshire, Somerset, Devon and Austria,' the court heard.

They included an ultra-modern home on the banks of the Beaulieu River in the New Forest, with a helicopter hangar, set in 27 acres, which is now the wife's home, and a listed country mansion near Horsington, Somerset.

As well as British Tour Car racing driver son, Alex, the former couple also have a, daughter, Lizzy, 27.

In his ruling last year, Mr Justice Mostyn described Mr Martin as 'a very active man' who 'loves shooting, skiing and motor racing.'

Describing the business empire he founded, Mr Martin told the judge: 'This is my life, my passion, it is the ultimate zing. It is as good as driving a racing car.'

The couple, who have two grown up children, 'enjoyed a very high lifestyle,' with a £5million home in Somerset (pictured)

Dextra was set up in 1978 and he bought out his business partner to take full control in 1989.

When dividing the couple's assets, Mr Justice Mostyn valued the company at the time the ex-couple started living together in 1986 at £44million and subtracted that from the pot to be divided between them.

He ruled the £44million was 'non-matrimonial assets', earned solely by Mr Martin.

Martin Pointer QC for Mrs Martin, told the Appeal Court today the judge got the valuation of the company when his relationship with Janie started in earnest drastically wrong, claiming it ought to have been valued at just £1.6million rather than £44million.

He also argued the judge went wrong by not factoring in the fact that Mr Martin only owned half the business in 1986, the other half then being owned by his former business partner.

Mr and Mrs Martin also had a £10million ultra-modern residence in Hampshire (pictured)

Using those calculations would reduce the monies to be taken out of the pot to just £800k, boosting the payout due to the wife by £17m.

'There was no reason at all to treat the husband as having had more than a half interest in Dextra' when they began living together, he told the court.

Mr Pointer also complained about Mr Justice Mostyn's decision to award £20million of the wife's payout in the form of shares in her husband's business

He said the wife 'shouldn't be just left hanging' and was entitled to insist on 'financial certainty and an absolute exit' from the marriage.

Instead, the divorce award had left her 'locked into an obligatory indefinite financial nexus with her ex-husband,' added the QC.

Judges were told Mr Martin spends £1million a year funding a motor racing team his 30-year-old son Alex drives for, and recently splashed out over £5million on an 860-acre shooting estate in Somerset (pictured)

Mr Martin had taken £8million out of the company in 2016, to pay for 'his new shooting estate', and also used his company to 'fund his motor racing with the parties' son at a cost of about £1million per annum,' said Mr Pointer.

'If the husband were able to continue to use the company finances in ways such as these, this would necessarily impact on the value of the wife's shareholding,' he added.

Lewis Marks QC, for Mr Martin, argued that the payout to his ex, far from being too small, was over-generous.

He said the judge had wrongly taken a 'risky high figure' when valuing the business at over £220million, having been told by a financial expert that it might fetch up to £35m less than that if sold.

'Unless the eventual sale of the business does achieve the judge's own figure, the working-out of his order is likely to result in the wife receiving a greater overall share of the assets than accorded with his own appraisal of the fair outcome,' the barrister added.

'Any enlargement of the wife's shareholding, as sought by her, would be likely to distort the balance between the parties so that her eventual share was greater than the husband's.

'Given the facts of the case, that could never have been a fair outcome,' Mr Marks told the court.

The hearing, before Lords Justice Simon, Moylan and Coulson, continues.