If, like millions of voters, you enjoyed the head-to-head election debates in 2015, I'm afraid the prospect of a repeat schedule became a little more tricky today.

We already know the Prime Minister doesn't want to take part in a head-to-head, insisting she has 'debated' Jeremy Corbyn every week in front of the parliamentary TV cameras for the best part of a year. That, and perhaps the fact that she is no fan of the media spotlight, or of its ability to find an inconvenient angle on the election campaign that isn't on the Conservative 'press grid'.

But today a source close to the Labour leader also ruled out his participation in any head-to-head debates which do not involve the Prime Minister. That could make it difficult for the broadcasters to 'empty chair' Theresa May in any such programming, as she now knows Jeremy Corbyn would also fail to show up.

The thinking on Labour's part may well be that the 2015 'opposition parties' debate that didn't involve David Cameron effectively served as extra promotion for other parties, such as Plaid Cymru, the SNP and Greens, detracting from the message that Labour was the one and only source of opposition.

So with Theresa May and Jeremy Corbyn both prepared to sit out a full-on debate in the format we've become accustomed to, that would only leave a handful of leaders of smaller parties willing to turn up. That doesn't rule out other forms of TV programming, perhaps allowing an audience or presenter to question each leader one by one, as happened in 2015. But the chance of Jeremy Corbyn and Theresa May being on the same stage at the same time does now seem fairly slim.