On Conservative Home, Mr Montgomerie notes that the Westminster village stories of the last few weeks - bullygate, Ashcroft, union links, lobbying and SamCamMam - have not had a significant effect on the polls. He suggests that there are really only four factors that move opinion polls in the long run:
The underlying state of the economy and voters' sense of which parties will best protect their household income.
The voters' sense of the party leaders.
The unity of the parties.
A winning, believable policy.
Mr Montgomerie, of course, looks at these factors from a Tory perspective. But what should Lib Dems think if he is right?
Whatever Mr Darling announces today, we can be sure that Vince Cable's sainthood with the public will continue. He is the most favoured Chancellor according to a recent poll and can be relied upon to tell it as it is, good or bad. He is clearly one of the Lib Dems biggest assets.
As for the Party Leader, I honestly believe that Nick will find increasing favour with the public as the election progresses. He has managed to stay out of the the slanging match during PMQs and the ITV interview on Sunday had him coming across as a genuine and likeable bloke.
The unity of the Lib Dems is very solid at this time. Of course we need to keep it together. But we don't have the rabid right wing that dogs the Tories or the huge splits that mean Brown is attacked from every side.
As for the policy, it is not for me to say. Of course I believe that it is right for the country. I hope that we have the space to articulate it clearly. But, inevitably, it will be down to the spokespeople we put forward to sell the policy and the party to campaign on the right issues in the right way. But this is the great imponderable for all the parties. And it is on this that we will ultimately stand or fall.
I would suggest that we should be looking forward to significant poll gains on that basis. As I posted previously, the Party secured a decent poll rise on the back of a strong and united Spring Conference. With the media attention dropping away a bit, this boost has slightly dissipated, but the better coverage that comes with the election announcement should restore things.