The president of the European Parliament is under pressure to justify his 46-strong entourage.
The office of Hans-Gert Poettering includes three drivers, 13 advisers and seven press officers.
A conservative estimate of the total annual running costs of the German MEP's cabinet alone has been put at €3.5 million (£2.5 million).
This includes about £1.6 million on staff salaries, plus travel expenses and publicity costs. Klaus Welle, his German chief of staff, is the top earner but six department heads directly below him are also believed to receive six-figure salaries.
The number of people in the centre-Right MEP's team has come under increased scrutiny by parliamentary colleagues because it is thought to be significantly bigger than any of his predecessors.
The department is financed by the parliament's £1 billion annual budget and its size dwarfs that of Jose Manuel Barroso, the president of the European Commission, who has 29 full-time staff in his office.
Nigel Farage, leader of the UK Independence Party, has now written to Mr Poettering demanding a full breakdown of the costs involved in running his office.
Under the parliament's rotating presidency, Mr Poettering's two-and-a-half year term ends after the 2009 European elections.
The president, traditionally the "face" of the parliament, represents the assembly in its international relations and chairs key meetings. His spokesman, Katrin Ruhrmann, said: "The role of president is crucial and it is important to point out that the size of his cabinet is only slightly bigger than that of his immediate predecessor.
"You also have to bear in mind that, as the parliament has grown in size and competences in recent years, so has the role of its president.
"He has to attend many meetings and undertake lots of overseas trips where he has to be briefed by his team of advisers."
