The SFO said on Thursday the extra funding was needed in part for its inquiry into Libor (London interbank offered rate) benchmark fixing, a probe into Barclays' (>> Barclays PLC) fundraising from Qatar, a Rolls Royce (>> Rolls-Royce Holding PLC) investigation and to meet costs linked to a 300 million pound damages suit launched by the property moguls the Tchenguiz brothers.

"This funding is 'blockbuster' funding for the course of our investigation and prosecution work in the remainder of this financial year," the agency said in a statement.

Solicitor General Oliver Heald said the Serious Fraud Office (SFO), which can request extra cash from the Treasury (finance department) as so-called "blockbuster funding" to beef up a tight annual budget of around 28 million pounds, needed an 11 million pound advance on the 19 million urgently.

"The SFO has incurred higher than anticipated expenditure and a reserve claim has been agreed by HM Treasury as part of the supplementary estimate 2013-14 process," Heald, a government lawyer, said in a written ministerial statement.

"The advance is required to meet an urgent cash requirement on existing services pending parliamentary approval ...," he added.

The SFO, which last requested such funding five years ago, has already received 5 million pounds in blockbuster funding for the financial year to March 31.

SFO head David Green, who took over as director in April 2012, has been tasked with restoring confidence in the agency by bringing criminals and companies to book after a period of mismanagement that has damaged the SFO's reputation.

He has staked his reputation on the success of high-profile investigations such as the sprawling global investigation into Libor manipulation.

Emily Thornberry, the opposition Labour Party's "shadow attorney general" or spokeswoman on judicial affairs, said it was entirely predictable that the scale and pace of budget cuts inflicted on the SFO would make it impossible for the agency to prosecute its caseload.

"This is not a government that takes economic crime seriously, which is why it is allowing the SFO to stagger from crisis to crisis and providing temporary sticking plasters where what is needed is a long-term plan to put it on a sustainable footing," she said in an emailed statement.

(Editing by Jane Merriman)

By Kirstin Ridley and William James

Stocks treated in this article : Rolls-Royce Holding PLC, Barclays PLC