HMRC to appoint assessor to oversee tax settlements with big businesses

The commissioner, who will be a senior official within the department but who will not have a role in any taxpayer's individual affairs, will be responsible for "protecting the interests of taxpayers at large", HMRC said.

The new arrangement is intended to address issues raised in a report into of alleged 'sweetheart' deals entered into between the department and large companies, including Goldman Sachs and Vodafone, published by the Public Accounts Committee (PAC) at the end of last year.

"This commissioner will take the role of challenging whether any proposed settlement secured the correct amount of tax efficiently and that taxpayers had been treated even-handedly. The commissioner will also make sure that the governance procedures have been followed. This deals with one of [the PAC's] key concerns - and in a way that is practical, affordable and does not require legislation," said HMRC chief executive Lin Homer.

However tax law expert Ian Hyde with Pinsent Masons, the law firm behind Out-Law.com, said that the announcement may not silence all HMRC's critics.

"This is HMRC's attempt to show it doesn't do 'sweetheart' deals with big business – it is all about HMRC's PR and nothing about proper management of tax collection. For most businesses, for which the customer experience is still of an aggressive and over-zealous HMRC, the issue is whether the department will engage positively and realistically in managing their tax affairs," he said.

An expert tax commissioner decision is currently required for tax settlements of £250 million or more, but under the new arrangements any case above £100 million will be referred to a panel of three commissioners including the assurance commissioner. HMRC said that this would "almost double" the number of settlement cases subject to extra scrutiny.

The assurance commissioner will also carry out a "systematic review" of the processes currently used by HMRC in settlement cases.

The department has also promised an enhanced role for its Audit and Risk Committee on settlement work, which includes representation from independent watchdog the National Audit Office. It will also introduce a new code of governance for tax disputes and publish an annual report on its settlement work.

David Gauke, Exchequer Secretary to the Treasury, said that the new arrangements would ensure a "clearer separation" between HMRC officials who negotiated settlements and the commissioners who considered them. Permanent Secretary for Tax Dave Hartnett, who recently announced his forthcoming retirement, had been particularly criticised by the PAC for his role in a high profile settlement involving investment bank Goldman Sachs last year.

"Settlements form an important part of HMRC's large business strategy. This internationally recognised approach has not only led to an increase in tax collected in recent years, it is contributing to the Government's drive to make the UK more competitive in a global market. This will continue to be vitally important as we work to rebuild our economy," Gauke said.

The Government collected £67.7bn worth of tax from the UK's hundred largest companies in the year ending March 2011, according to new research from accountancy firm PwC.