National interests creating tension in EU commission

"Of course it is much easier when you come from a small member state where national leaders don't really attempt to influence the course of EU history," the commissioner added.

The implication that EU legislation is subject to the whims of powerful national capitals such as Berlin, Paris or Rome is nothing new. But the financial crisis and an enlarged union with greater powers for the Brussels-based institutions are all contributing to growing pressure, say seasoned observers.

"The bigger the EU becomes the more it becomes intergovernmental and the more the commission is regarded as an executive secretariat for the council," says Belgian MEP Derk Jan Eppink, a member of the European Conservatives and Reformists group in parliament.

Author of Life of a European Mandarin – Inside the Commission, Mr Eppink previously worked in the cabinets of former commissioner Frits Bolkestein and subsequently that of Siim Kallas.

"Commissioners from larger member states frequently feel they have to produce the goods for their governments back home, while those from smaller countries realise they don't have the capacity to do this," he said, pointing to former commissioner Gunter Verheugen's willingness to stand up for German industry.

Another official identified issues of public procurement, state aid and EU infringement cases as areas where national lobbying is frequently intense.

"Senior Italian officials within the commission are known for arguing their national case overtly," the contact said. The source added that the practice of defending a member state view is not necessarily "anti-European," as it can prevent blockages further down the EU legislative pipeline.

Targeting Barroso

Commission chief Jose Manuel Barroso's presidential style of running the EU executive - compared to the more prime ministerial approach adopted by his predecessor Romano Prodi – has reportedly led to greater lobbying efforts to gain his attention.

"Mr Barroso can stop a piece of legislation or push it through, so big member states will try to catch his ear," said Mr Eppink.

"When it doesn't happen they let him know about it," he added, pointing to the recent Roma squabble, in which Mr Barroso is seen as having backed down after French President Nicolas Sarkozy voiced his anger over the commission's approach to France at a recent EU summit.

A number of commissioners are also known to be furious with Mr Barroso's recent attempts – under intense pressure from Germany - to stall an EU initiative to phase out subsidies to loss-making coal mines by 2014.

Special chefs

While clashes during the weekly college meetings are not unknown, the real shouting matches frequently take place at gatherings of the commission "special chefs" - officials in each of the 27 cabinets in charge of a certain area.

These highly political meetings take place roughly one week before the college adopts a given proposal, with participants keen to secure all-important last minute changes according to their masters' wills.

Based in Brussels, member state permanent representations to the EU are known to play a key role in national lobbying efforts, frequently preparing notes for the cabinet of 'their' commissioner, outlining which position officials should take on a particular issue.

Not all capitals get their way however, with a change of government back home frequently leaving the new administration with a commissioner from a different political family who may be less inclined to adopt the national line.

As such, commission vice president Catherine Ashton – a Labour politician - could be less likely to listen to the new Tory-Liberal administration in London. Sources say Dutch commissioner Neelie Kroes is among those who rarely take direct orders from back home.