David Cameron will emerge from this week's expected defeat over the appointment of Jean-Claude Juncker as EU Commission president straight into what may prove an even more damaging battle over the biggest job in Europe.

The man who heads the European council of all EU leaders, Herman Van Rompuy, ends his five year term in office in November and there is set to be a battle royal over his replacement, to be chosen by those leaders.

Once again it is likely the battle lines will be drawn between those like Cameron and the UK who want to scale back the EU's ambitions and those, like Juncker and many other EU states, who have a more federalist agenda.

And, while the EU Commission job is powerful, the position of Council head is arguably even more significant as the post holder is, in effect, the real "President of Europe".

Helle Thorning-Schmidt dances with Neil Kinnock PIC: Reuters
Helle Thorning-Schmidt dances with Neil Kinnock

So far the UK has not announced a candidate although names have been floated elsewhere in Europe, including former Labour leader Neil Kinnock's daughter-in-law Danish premier Helle Thorning-Schmidt.

She had been touted as a possible compromise candidate instead of Juncker as Commission president but was allegedly unenthusiastic. Many believe she would be a perfect high-profile yet unifying candidate for the council job.

That post was only created in its present form by the Lisbon Treaty in 2009 and the first holder was given virtual carte blanche to define his own role. Tony Blair was amongst the leading runners at that time amid suggestions he would create a high-profile, highly political and hands-on job.

He failed to be selected for a number of reasons including the fact the UK was not in the euro and his role in the Iraq war which had made him a hugely divisive figure.

Ironically, Juncker's name was also floated but, in the end, the leaders chose Van Rompuy as an administrator figure who took a more low-key, some say near-invisible, and certainly uncontroversial approach.

But with the EU clearly at a pivotal point in its evolution following the recent elections, it is thought the leaders may go for a more pro-active, high-profile candidate who can forge a clear global identity for the EU – the single person other national leaders, such as the US President or Chinese premier call when they need to speak to the EU.

According to the job description, the Council president is: "the principal representative of the European Union on the world stage, and the person presiding over and driving forward the work of the European Council.... and provides political direction to the European Union".

The council not only includes all 28 national leaders but also the Commission president, in effect making it the more senior of the two top Brussels jobs.

The candidate will therefore have unprecedented power to drive forward the political direction of the EU. The process of selecting the individual will kick off during this week's summit, although it will mostly be kept behind closed doors to allow the long period of horse trading to get underway.

Cameron may find his position has been weakened by his unbending and vocal opposition to Juncker although his supporters, who admire his refusal to back down even in the face of defeat, have suggested the other EU leaders may be in a mood to placate him after the very public snub

Either way there is the potential for this contest to be as bruising for the prime minister as his current anti-Juncker campaign. But it will also be a hugely significant indication of where the EU sees its future direction, and the UK's part in it.