Image copyright BBC Newsline Image caption Frank Cushnahan, a former banker, was a Nama adviser from May 2010 to November 2013

Ex-finance minister Sammy Wilson has backed the businessman at the centre of the scandal over the biggest property deal in Northern Ireland's history as "a friend" who had done "great work".

Nama sold its NI property loan portfolio for £1.2bn in 2014.

Frank Cushnahan's role in the deal has been the subject of controversy.

Mr Wilson said it should be the police who decided whether Mr Cushnahan had done anything wrong, not "a bunch of amateurs in (BBC) Spotlight".

'Bag of cash'

Mr Cushnahan served as an adviser to Nama between 2010 and 2013, having been nominated to the Nama NI advisory committee by Mr Wilson, who was then the finance minister.

Earlier this month, a BBC Spotlight programme broadcast a recording of a meeting in which Mr Cushnahan was handed a bag containing £40,000 in cash by a Nama client, John Miskelly.

In his first interview since the Spotlight programme was broadcast earlier this month, Mr Wilson said: "Frank Cushnahan is a friend, he did great work for me when I was in the department."

The DUP MP told the BBC's Talkback programme: "I would prefer if the people who would determine whether Frank did anything wrong or not was not a bunch of amateurs in Spotlight, who in my view have an agenda, but I would prefer if the police would deal with that."

Image caption Sammy Wilson said Mr Cushnahan did 'great work' for the finance department when Mr Wilson was minister

Nama has reported Mr Cushnahan to the National Crime Agency and the Irish police.

He has denied any wrongdoing and both he and Mr Miskelly have said that their dealings were "lawful".

Mr Wilson, who said he had not seen the Spotlight programme, said: "He did a good job when I was in the department.

"He made firm representations for Northern Ireland with Nama and Nama had a big influence on a lot of properties and businesses in Northern Ireland.

"As far as I'm concerned this is an issue that the police will deal with and not a bunch of journalists who have an agenda."