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David Cameron says he'd pass a law to convince us his election promises are genuine - and Ed Miliband has literally had his set in stone. 8ft high stone no less. Today, the Labour leader is focusing on tuition fees - specifically his plan to reduce them from a maximum of £9,000 to £6,000 - and tying Nick Clegg's infamous U-turn with David Cameron's failure to achieve his "no ifs, not buts" promise to cut immigration.

BBC Radio 5 Live

The parties appear to be in stalemate in the polls, Professor John Tonge, from the University of Liverpool, tells Radio 5 live. "With just over 96 hours until the polls open, what is going to change? The parties are neck and neck, they've cancelled each other out on the biggest two issues of the election - the economy... [and] the NHS..." This isn't down to the quality of the campaigning, though, which has improved in the run-up to the election, he says.

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We know you like to plan your Sunday, so before you dash out to the park or the pub, like Nigel here, let us fill you in on what's coming up politics-wise.

On the Andrew Marr Show, at 9am on BBC1, we're expecting Lib Dem leader Nick Clegg, UKIP leader Nigel Farage and Labour shadow home secretary Yvette Cooper.

Next, on Pienaar's Politics on BBC Radio 5 live at 10am, there's an economy theme to things with Chancellor George Osborne, shadow business secretary Chuka Umunna and Chief Secretary to the Treasury Danny Alexander.

On the Sunday Politics - BBC2 at 11am - the guests will be William Hague, SNP MSP and deputy first minister John Swinney and US political expert Frank Luntz.

Finally, Ed Balls will be appearing on The World This Weekend on Radio 4 at 1pm.

BBC Breakfast

The Lib Dems' red line on public sector pay is the fifth in a week, BBC politics correspondent Ellie Price tells BBC Breakfast. "Probably the most difficult [red line] to square off with other parties, particularly the Conservatives," she says. "Of course the Lib Dems got their fingers burnt last last time round when they said that they would scrap tuition fees, and they ended up voting to increase them."

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Looking at the last 20 published polls of the campaign, they suggest to me that any recent Conservative increase in support has stalled in the past few days; Labour slogs on at around 34%; the Lib Dems at about 9% and the Greens around 5%. Once again UKIP is the most intriguing part of the 2015 electoral equation: the fortunes of other parties rest so heavily on their performance. My reading of the latest polls suggests to me that their support is holding up rather than disintegrating.

As a child I remember a seaside booth where a Madame Osiris offered to reveal all the secrets of the universe for just £5. I must confess that I am not in her league. I have never been more uncertain about the outcome of a general election in my life. Before the explosion of the SNP in Scotland I would have gambled that Labour were most likely to emerge as the largest party in a hung parliament: Scotland wrecks that and makes the possibility of the Conservatives ending up with most seats very plausible. What makes this a really difficult election to call is that the small number of seats that will determine who is ahead in an election that nobody wins could well be decided by organisational slugfests in a handful of parliamentary seats.

As you'd expect, there's acres of royal baby coverage this morning in the papers, but there are also some politics stories too. The Independent, external is leading with pitches to the electorate from Ed Miliband, Nick Clegg, and David Cameron - with Nick Clegg saying he wouldn't go into a Conservative coalition "against the collective will" of his party. The Sunday Times, external has an article about Labour's warning on tuition fees. The Sunday Telegraph, external is saying that the UK faces "weeks of political chaos" following the election, and The Observer, external says Britain faces "political paralysis".

The home stretch at last but one littered with unknowns. Is there a late rally to the Conservatives? Possibly, but like so much else in this campaign, it seems far from clear. Will Labour out-perform the national polls by performing more strongly in key marginal seats? There is some supporting evidence for this but it is hardly overwhelming. How to reconcile the Lib Dems holding many of their seats when support for them in the national polls has collapsed? Will UKIP’s support dissolve on 7 May and produce a hidden army that delivers victory to the Conservatives? Will the polls overstate Labour’s support this time, unlike 2010 when they understated it? Will Scotland return any other than SNP MPs?

We would not be in our present confusion about the outcome of the general election if the three main Westminster parties were popular. All our problems in trying to predict the outcome of 7 May stem from the fact that they are manifestly unpopular. This general election is the mother of all ugly baby contests between the Conservatives, Labour and the Lib Dems. And yet, for all the public antipathy towards mainstream Westminster parties, no other parties under our current first past the post system, are going to form a government, minority or otherwise. So, back to the grindstone.

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The Lib Dem promise on public sector pay is the latest in a series of red lines - in plain English, conditions - that Nick Clegg has been placing on any coalition deal involving his party. For their part, the Conservatives say they plan to continue "restraining" public sector pay, while Labour's manifesto says any decisions in the next Parliament must "prioritise those on lower incomes", be evidence based, and respect pay review body recommendations.

The other Lib Dem red lines announced so far are:

- guarantees on education spending

- a £12,500 personal income tax allowance

- £8bn extra a year for the NHS

- an emergency "stability budget"

Well, there are fours days left until the election. It's Victoria King and Tom Espiner here for Politics Live. Labour will today restate their pledge to cut tuition fees to £6,000 and they claim that the scale of Conservative cuts means they will have to raise them to £11,500. And the Lib Dems have drawn yet another coalition red line - this one on public sector pay .