Financier Derek Quinlan kept up his lifestyle of a "successful investor" in the midst of severe financial difficulties to maximise the amount of money he could make from selling his assets, it was claimed in court today.

Mr Quinlan came under severe criticism for his "lavish lifestyle" of expensive cars, private jets and luxurious holidays following the collapse of property prices.

Billions worth of his debt also came under control of the Irish taxpayer through NAMA.

But today in court it was claimed Mr Quinlan found it vital he maintained his lifestyle so he did not appear as a distressed seller.

The High Court in London heard Mr Quinlan's main aim after the property collapse was to sell his assets to the benefit of his creditors.

At one point Mr Quinlan owed €3.7bn to various Irish banks and NAMA.

In a statement to the High Court, Mr Quinlan's associate Gerry Murphy stressed how important the lifestyle was to get a good price for his assets.

Mr Murphy and Mr Quinlan took the stand in the case of Coroin - the £1bn hotels group that owned Claridge's, Connaught and the Berkeley.

Mr Murphy said: "Mr Quinlan also took the view that in order to maximise the value of his various interests it was vital that he did not look like a distressed seller.

"On that basis it was clear that style was as important as substance and it was vital that Mr Quinlan maintained his lifestyle as a successful investor.

"By doing so he was not only maximising the price of his own shares but also the value of other investors' shares in the company."

Mr Quinlan is the second respondent in a case brought by Belfast-born developer Patrick McKillen against billionaire twins, the Barclay brothers. The brothers purchased a 25% stake in Coroin in January last year.

Mr McKillen claims the brothers and Mr Quinlan colluded to deny him the opportunity to buy a crucial further stake in Coroin.

He said the two acted as combined interest to control the company at board level and also alleged David Barclay had paid the Quinlan family almost £3m in a year as an inducement for him to sell his shares in Coroin to them.

But Mr Murphy told the High Court he acted for Mr Quinlan on the board of Coroin after the shareholders began to "marginalise" him following his financial difficulties in 2009.

Mr Murphy denied the payments were an inducement to sell shares and said the brothers had taken a "keen interest" in the welfare of the Quinlan family and were keen the see the investor "get back on his feet".

He said Mr Quinlan and the brothers would meet on a weekly basis in Monaco in 2010 to share "coffee and cigars".

He told the court the payments from David were made to Mr Quinlan's wife Siobhan who would then pass them on for the purpose of running the financier's office.

He said: "The Barclay Brothers obviously meant it when they said they would help Mr Quinlan get back on his feet.

"For example, in October 2010 they gave Mr Quinlan financial support when they gave him a loan of €500,000 to help pay his Swiss tax bill and some other expenses. There were no conditions attached to this personal loan."