Press Association reports that thousands of people have signed up to a website aimed at reducing the number of "wasted" votes in the election.

On www.swapmyvote.uk, external two people agree to vote for each other's preferred party in their constituency. The belief is this will make someone's vote count for more in a constituency where it could make more of a difference.

Tom de Grunwald, who has helped to develop the site, said:

Image source, PA

It's been a day of door-knocking and media appearances for Nigel Farage. On BBC's Sunday Politics show, he turned his ire on the prime minister and accused his bombing in Libya of being the reason for so many disasters at sea involving migrants.

Deputy PM Nick Clegg says he has no regrets over Libya but an urgent review by the EU was needed.

Carole Walker
BBC Conservative campaign correspondent

Two weeks into this closely-fought contest and David Cameron is trying to rework another Thatcher hit from the 1980s. Ed Miliband is embarking on a week of campaigning on Labour's favoured home territory of the NHS. They both appear to be out to convince and reassure their own natural supporters. Neither seems poised to make a dramatic breakthrough and win an overall majority.

The polls suggest the only party on course to make big gains is the SNP which could end up with as many as 50 MPs at Westminster. Hence the increasingly fevered speculation about what role they could play in determining who governs the country.

David Cameron is ratcheting up the rhetoric on the dangers of a Labour government propped up by the SNP, warning of a group of nationalists coming to Westminster to break up the country.

Labour and the SNP have ruled out a coalition. But Labour's Angela Eagle has kept the door open to a vote-by-vote deal with the SNP, saying her party would speak to any other party represented in the Commons to build a majority for its Queen's Speech.

The SNP will launch its manifesto tomorrow. Stand by for more arguments about what sort power and influence the nationalists might wield at Westminster - and what that will mean for the rest of the UK.

Here's Ed Miliband being accosted by a woman about a deal to use Croydon's Ashburton Library as a place of worship – agreed with the previous Conservative council but scrapped by the new Labour administration. As she gets louder and shortly after she says: "We’ve always voted Labour", she’s ushered away by (we assume) a Labour staffer.

Foreign Secretary Philip Hammond said the "world is horrified at the appalling loss of life that it is taking place in the Mediterranean", referring to the deaths of an estimated 700 people after a boat carrying migrants capsized . He went on:

"I discussed ideas for effective action with G7 foreign ministers last week and will do so again with EU foreign ministers at our meeting in Luxembourg tomorrow.

Celebrities and politicians are taking to Twitter to try to get #register2015 trending as part of efforts to encourage people to register to vote before midnight tomorrow.

Satirist Armando Iannucci, who created the political sitcom The Thick Of It, tweeted, external : "It only takes 5 mins to register to vote. Do it here. gov.uk/register-to-vo…, external . This election is SO close, every vote counts. #register2015, external "

To register to vote, visit this website, external or return a paper application in person to your local council headquarters before the deadline.

Much of today's debate has surrounded Nicola Sturgeon and who she - and her party, the SNP - might work with, should they get the opportunity come 8 May.

She's a household name in Scotland and, thanks to the recent televised debates, she's rapidly becoming well-known in other parts - but what does the rest of the UK think of the SNP leader?

The BBC's Nick Eardley took a look earlier this month...

There are 18 days left until the election. Here are today's key developments:

- David Cameron promised voters the chance to buy Lloyds bank shares at discount prices if the Conservatives win the election

- He also warned of the "frightening prospect" of a Labour-SNP coalition and said the Nationalists wanted to get into Westminster to "break up our country"

- SNP leader Nicola Sturgeon ruled out any deal with the Conservatives and dismissed Mr Cameron's claims

- Lib Dem Vince Cable said it would be difficult to work with either Labour or the Conservatives but the party would do so in the national interest

- UKIP leader Nigel Farage warned of a "complete stitch-up" on an EU referendum if Mr Cameron wins a majority

- Lib Dem Ed Davey warned "Huge discounts" offered in right-to-buy schemes had led to fraud

tweets, external :

The "huge discounts" offered in right-to-buy schemes have led to fraud, Energy and Climate Change Secretary Ed Davey has claimed.

The Liberal Democrat told the BBC the schemes had seen "a lot of fraud going on, even money laundering".

The Conservatives have said they would extend the right-to-buy for tenants of housing associations.

Full story here.

Peter Hunt
Labour campaign correspondent

The Conservatives are facing questions about what sort of deal they'll do with UKIP and Labour are being asked about what sort of deal they'd do with the SNP. Both parties are criticising each other for not coming clean but neither will rule out anything either - so it's a case of do as I say, not as I do.

Image source, Getty images

The Queen has been attending a reception at London's Canada House today.

But which potential prime minister will she be inviting to Buckingham Palace come 8 May?

Read more about the Queen and prime ministers here., external

Lib Dem leader Nick Clegg has been speaking about the Conservatives' plan to offer billions of pounds worth of shares in Lloyds Banking Group to the public, should they win the election:

... from Victoria King and Tom Espiner.

Thanks for joining us for a busy Sunday so far, dominated by talk of the ins and outs and ups and downs of potential coalitions, deals and non-deals after 7 May.

Aiden James, Marie Jackson and Gerry Holt are taking over now and will bring you all the rest of this Sunday's election developments as they happen.

Plaid Cymru could withhold support from a minority Labour government, Leanne Wood has said. Plaid says it will work with Labour if it does not get an outright majority but Ms Wood told BBC Sunday Politics Wales that did not mean unconditional support.

Full story here.

Chris Cook
Newsnight Policy Editor

Image source, PA

There's a lot to be said for getting assets into the hands of the public. But banks are definitely riskier vehicles for mass shareholder capitalism than telephone companies. Read more of Chris's thoughts.

Image source, PA

Scottish deputy Labour leader Kezia Dugdale - and obligatory campaign baby - look like they're having a rather bracing trip to the beach near Edinburgh.

Image source, PA

Lib Dem leader Nick Clegg would not rule out forming a coalition which would help install the leader of the second-placed party in Number 10. At a rally in Portsmouth's Spinnaker Tower, Mr Clegg said: "Legitimacy is everything, particularly when you move into an era of coalition government, which was why I was so adamant last time that the party with the largest mandate, notwithstanding the fact that they didn't have a majority, should be given the time and the space to try and assemble a government... [but] just for the sake of argument, if a larger party, with more votes and more seats, can't or chooses not to create a stable government, then we need a government in this country. At the end of the day, one way or another, a government needs to be formed."