How "unprecedented" is this week's business letter?

"An intervention on this scale and with this clarity from Britain's business leaders is unprecedented in any recent general election." George Osborne, Wednesday 1 April

After a letter signed at first by 103 business leaders and then by a further 17 chief executives was published by the Daily Telegraph yesterday, George Osborne said the endorsement was "unprecedented" in this scale this close to a recent election.  We can't be sure what he means by "recent" or by "scale". But as open letters are a regular feature of public debate around elections, we looked back at a few other examples.

Many newspapers have pointed out that by the time of the 2010 election 68 business leaders had signed an open letter to the Daily Telegraph arguing that Labour's planned increases to National Insurance should be scrapped. Later on in 2010, 35 business leaders wrote in support of George Osborne's plans for cuts in public spending.

On 21 May 2001, ahead of the 7 June election, a grander total of 140 businessmen and women wrote to the Daily Telegraph to say that Britain was "being taken in the wrong direction" by the then Labour government. Perhaps George Osborne is not counting this letter when he talks about yesterday's letter being unprecedented in any recent election because it happened too long ago.

Business leaders' letters have chimed in on other topics too; for example in 2013 business leaders wrote an open letter to say that a big change in the UK's relationship with the European Union would harm British business, in response to Conservative thinking on an in/out EU referendum. In 2003 The Times reported that "more than two dozen business leaders" sent Tony Blair an open letter asking him not to rule out joining the the single currency.