Blog: We’re into the penultimate week of this long election campaign, and the weekend opinion polls were telling a now familiar story that this is a three-horse race and that we’re heading for a hung parliament.

Unless the Liberal Democrat bubble bursts over the next 10 days, no single party will have gained sufficient seats in the Commons to be able to govern the United Kingdom on its own.

But on my travels around marginal constituencies in Shropshire, Staffordshire and the Black Country last week, I discovered that there is a very large fourth force out there who will decide the outcome on May 6.

They are called The Undecideds.

Wherever I went, among the terraced houses close to Wolverhampton city centre or in the rolling countryside of South Shropshire, the message was the same: “I haven’t made my mind up yet.”

For some, this answer will have been a defensive mechanism not wishing to tell a particular party candidate that they will vote for the other guy or gal, or that they have no intention of walking down to the polling station a week on Thursday.

But for others there was genuine uncertainty in their minds. Some had become disillusioned with politicians of all parties following the expenses scandal; others were fed up with Labour after the initial hope offered by Tony Blair in 1997 had slowly been eroded.

They weren’t too sure about David Cameron, and there are some Tory policies which worry them, including the foxhunting ban, an issue which has hardly featured in the campaign.

Now there’s this other chap, Nick Clegg. Seems like a nice young man, speaks well, and maybe it is time to break up the Labour-Conservative duopoly that has dominated UK politics since the 1920s.

The Lib Dem leader also had some other interesting things to say yesterday about the coalition government which will have to be formed if the opinion polls accurately reflect how people will vote on May 6.

It seems inconceivable that the man who has railed against the old two parties’ refusal to contemplate meaningful political reform could then prop up Mr Brown in Downing Street if Labour ends up coming third.

So he attempted, but didn’t quite manage, to rule out this prospect yesterday in an interview on the Andrew Marr Show.

Mr Clegg seemed to be on offer to anyone, including Gordon Brown and David Cameron, if “miracle of miracles” they agreed with the big political, social and economic changes he wanted.

Trouble is, Nick, miracles don’t occur in politics.

By John Hipwood