NAMA's Project Eagle loan book was at the centre of a major legal and political discussion four years ago - and now it is creating headlines once again.

But what was Project Eagle, and why has it attracted so much attention?

What was Project Eagle?

Project Eagle was the code-name given to the portfolio of Northern Ireland-based loans held by National Asset Management Agency (NAMA) - the State's bad bank.

It was one of a number of portfolios managed by NAMA, based on bad loans it acquired from Irish banks following the bailout.

In 2014 it sold the loans in one block to US fund Cerberus for £1.3bn - however that deal later came under scrutiny from a number of different bodies.

What issues were raised with the deal?

The sale was reviewed by the spending watchdog the Comptroller and Auditor General (C&AG), which said there were serious shortcomings.

Its most controversial finding is that the loans were sold with a "probable loss of value" to the State of up to £190m or €220m.

It also raised questions about selling the loans in one tranche as opposed to breaking them up.

At the time NAMA defended the price and said it represented the best value available for the loans.

Separately allegations of impropriety were made relating to the deal, including allegations made in the Dáil by then TD Mick Wallace and a BBC Spotlight investigation.

It emerged the successful bidders, Cerberus, had paid £15m to its lawyers following the sale, some of which ended up in an Isle of Man bank account as a fixer fee.

NAMA’s CEO Brendan McDonagh said allegations of wrongdoing were being made about the buyers, not the sellers.

What's put it back in the news?

The deal was subject to an investigation by Northern Ireland's National Crime Agency, which subsequently submitted a "complex and substantial file" to the Public Prosecution Service.

It has now decided to bring charges against two men - a 78-year-old and a 49-year-old.

It also decided not to prosecute six other individuals reported in connection with the Project Eagle deal, as it concluded there was insufficient evidence.