Promise me a date if I just deliver these 60 tonnes of nanotech to Reticulon Blarg, three solar systems away, on Twitter.

FORBES: Connect

There is diplomacy to be done at home as well as abroad with Tory Eurosceptics who will question the worth of a referendum promise without a date attached and who will demand to know what the prime minister would do if he cannot get his way in negotiations.

BBC: Europe - Why Cameron's speech is proving so hard to write

On 2 June he won a no confidence vote in the Diet (parliament), only by making a promise to step down at a future date.

BBC: Japan PM Naoto Kan announces resignation amid criticism

Candidates must not currently hold a permanent academic post, or have ever held a permanent academic post in the past, or have received, before the start date of the award, the promise of a permanent academic post.

UNESCO: UK National Commission for UNESCO :: UK and Ireland National Fellowships

So, in summary, the IPO Classes of 2010-2011 have seen mediocre to poor performance to date, although a couple of outliers have some promise.

FORBES: A Look Back at 2010-2011 Class of Biotech IPOs: Not Dead Yet

Indeed, not only has he set no date for entry, but he will not even promise to join in the lifetime of the next Parliament.

ECONOMIST: Tony Quixote finds his windmill

While Mr Farage criticised the decision to delay the vote by five years, he claimed the prime minister's promise showed "we have changed the political agenda in this country" calling it "our proudest achievement to date".

BBC: How UKIP became a British political force