Scottish First Minister Nicola Sturgeon has said she believes it is "a matter of when, not if" Boris Johnson is forced out of office over the Downing Street party scandal. <br /> <br />Launching the SNP's local election manifesto on Friday, the party leader criticised the prime minister as a "clown" whose conduct and policies were "not funny". Report by Buseld. Like us on Facebook at http://www.facebook.com/itn and follow us on Twitter at http://twitter.com/itn
