UKIP leader Nigel Farage has accued David Cameron, Ed Miliband and Nick Clegg of "appalling weakness in the face of the aggressive tactics of the SNP", which he says will "threaten the future of the United Kingdom".
Mr Farage was speaking in response to the SNP's election manifesto, which was launched this morning.
Only UKIP will stand up for the interests of English voters and Welsh voters too. Only UKIP says that votes on matters only affecting England should be limited to English MPs at every stage of the legislative process.
Nicola Sturgeon gave an impressive performance today and she could have a very significant impact on an Ed Miliband government.
The SNP pledges a team of its MPs would deliver a "stronger Scotland" while behaving "responsibly and constructively" for the UK as a whole.