As a campaign nears its end, the overriding commodity all politicians desire to sweep them to victory is momentum.

On Monday, No 10 was adamant that the Prime Minister would not be going to Scotland this week and would be making just one visit next week as he fights with "every fibre" of his being to save the Union.

But as David Cameron's spokesman was telling the Lobby this, the PM and Ed Miliband were chatting privately in the Tory leader's room in the Commons on how they could do more to boost the flagging No campaign and reverse the tide that was apparently flowing in Alex Salmond's favour.

Clearly, the Tories are toxic north of the Border but Mr Cameron is desperate to get stuck in politically; he's a natural campaigner.

Downing Street would not tell us whose idea it was but it was decided that the UK triumvirate would each venture north tomorrow to 'love bomb' Scotland in separate locations.

The plan is to capitalise on the momentum created by Gordon Brown's passionate defence of the Union and his setting out of a Plan of Action to guarantee Scotland would get more powers over tax, spending and welfare in the next Westminster Parliament following a No vote.

So, as the polls narrow and Whitehall suddenly realises the threat to the 300-year-old Union is real, the game is now afoot and, with just a week to go, the passionate final flurry of campaigning will begin.

It is not beyond the realms of possibility that the Cameron/Clegg/Miliband love bombing will be repeated next week, possibly Wednesday on the last full day of campaigning, to convince those undecided voters and waverers to stick with dear old Blighty.