Labour 34%, Conservatives 32%, UKIP 17%, Liberal Democrats 7%, Green Party 6%

Source: Electoral calculus

The Labour Party increases its lead by 1% in this week's poll of polls. The Tories are down 1%, UKIP are up to 17%, their highest share since 7th December, the Liberal Democrats remain stubbornly low on 7% and the Greens shed 1 point to finish the week on 6%.

There is still no sign of the kind of breakthrough either the Conservatives and Lib Dems are looking for. One of the big stories in my polls for the last few weeks has been the steady decline of UKIP. This week, they have bounced back up again, with one poll by the ICM pollster putting them on 20% of the vote. It is difficult to say for sure why this is happening. However, one clue can be found in the polling on the link that I have provided: People believe David Cameron is trying to duck the debates, and many believe that he is simply using the exclusion of the Green Party as a convenient excuse. Considering the poor personal ratings of Mr Miliband, it is therefore conceivable that voters have looked at Farage and concluded that the PM is effectively running scared from him. Nobody likes a coward.

Sources close to the Prime Minister have said that he is determined not to take part, even if the broadcasters fold and decide to invite Natalie Bennett of the Greens onto the podium. Why? Because, even with the Green leader acting as a sort of competition for the anti-politics vote, Nigel Farage would probably still destroy David Cameron in a TV debate. Added to this, there is also the potential risk of Ed Miliband doing much better than expected, and therefore being able to set himself up as a credible alternative Prime Minister. The risk is just too great for the PM to gamble on.

Also, a reminder about the volatility of polling. A poll released earlier this week by Lord Ashcroft showed a conservative lead of 6%. It sent Labour MPs into panic mode. A few hours later, a Populus poll with a 5% Labour lead was released. Both have turned out to be innaccurate, as my polling average shows, but this should remind people to look at the broader trend, and not just one opinion poll.

Other major political stories of the week: GREEN SURGE

The Green Party has seen a surge in its membership figures over the past week, and now has more members than the Liberal Democrats. What trigered the surge was this article, which said that the Green Party could overtake the membership of the Lib Dems within a week.Whilst this surge is very encouraging for them, a note of caution must also be sounded. Over the same time period as the membership surge, the Green share of the vote has not risen significantly, and has actually dropped slightly in my poll of polls this week. Perhaps increasing membership does not necessarily translate into increased support across the country as a whole. On the other hand, the increase in membership must also increase the chances of the only Green MP, Caroline Lucas, being re-elected in May this year. She must surely now be considered the favourite to hold Brighton Pavillion.