The European Greens have backed their arch-rival Nigel Farage, the leader of the UK Independence Party (UKIP), in a row over the distribution of committee chairs in the European Parliament, saying his Eurosceptic group is being denied a chairmanship it deserves.

European Parliament committees will elect their chairpersons and vice-chairpersons next Monday in a vote that will see powerful posts distributed among the Parliament’s political groups.

But Farage’s Parliamentary faction, the Europe of Freedom and Direct Democracy (EFDD) group, will not obtain the committee chair it is entitled to, the Greens warned.

This is because the posts are voted on by the committee members in a secret ballot and the main parties have struck an agreement among themselves to share the spoils.

Hermann Kelly, a spokesman for the EFDD, denounced "a behind closed-door coup” by the three main pro-European parties – the European People’s Party (EPP), the Socialists and Democrats (S&D) and the Alliance of Liberals and Democrats for Europe (ALDE).

Although the Greens are convinced Europhiles, they protested against the move and gave their support to the Eurosceptic EFDD.

"Excluding any political group from a committee chairmanship to which it is due under the established system for fairly distributing these posts would be a blow to the democratic process in the EU Parliament,” said Margrete Auken, the Greens spokesperson on the Parliament’s petitions committee.

Under the D'Hondt system of appointment, committee posts are distributed among the political parties proportionate to the number of elected MEPs. The system is seen as a fair way of distributing key posts.

But the Greens said an agreement between the main political groups would mean the EFDD would lose the chair of the petitions committee, to which it is entitled under the D'Hondt system.

“This goes beyond petty politicking but to the heart of European democracy,” Auken said in an unexpected show of support for Farage.

“The candidate nominated by the EFDD group appears to have all the qualifications and the right approach to adequately exercise this duty. Against this background we strongly urge the other political groups not to go ahead with a coup against the D'Hondt system, which would jeopardise the necessary minimal cooperation that is needed to make this parliament work," Auken argued.

The EFDD's Kelly agreed and used the row to denounce the cosy pro-European backroom deals taking place in Parliament.

“If the big Europhile groups gang up to do the dirty concerning committee chairs then the flimsy facade of democracy, the pretence of the rule of law and any vestige of transparency will be washed away," he told EurActiv in emailed comments.