The Assets Recovery Agency operated for almost four years

Jane Earl said the Assets Recovery Agency's work was restricted by laws which prevented staff from chasing assets owned for more than 12 years.

Plans to close the body were announced in January.

Last year it emerged that the agency had recovered only �8m from criminals - despite costing �60m to set up.

The ARA, which operated in London and Belfast for almost four years, is to merge with the Serious Organised Crime Agency (SOCA).

Government sources have insisted that while the ARA will cease to exist in name, its work and investigations will continue.

However, in her first interview since plans to scrap the body were announced, Ms Earl said legislation put many serious criminals beyond the agency's reach.

She said certain criminals "made much of their criminal proceeds back in the 1980s and they are clearly outside the grasp of the law".

Ms Earl went on: "There are key people who we could never go after simply because of the limitation period."

She said that the ARA had lived up to "very high expectations" in some respects, but it could never have gone after more established criminals, as had been expected.