The Mayor of London, who is standing in the constituency of Uxbridge and South Ruislip, said his party will give people a say on Europe and immigration - two big policy pledges by Nigel Farage's Ukip.
In a plea to Ukip supporters, he said: "My message to Kippers is this: grit your teeth, screw up your eyes, take a deep breath and do the right thing for this country."
Mr Johnson claimed a Labour-SNP government would be a "supine, useless, federalist" one.
Ed Miliband has ruled out a coalition or deal with the Scottish nationalists.
During his section of Question Time last night he said: "If the price of a Labour government is a coalition or a deal with the SNP, it is not going to happen."
Mr Johnson said he would make sure there is a referendum on Britain's membership of the EU should the Tories return to power.
Read more:
http://www.express.co.uk/news/politics/574189/Boris-Johnson-Conservatives-Tory-Nigel-Farage-Ukip-UK-Independence-Party-election-May-7
