The SNP's Westminster leader has said that Dominic Cummings is a "key witness" into the Downing Street party probe and without him "the inquiry will not be worth the paper it is written on".
Boris Johnson's one-time top aide accused his former boss of lying to Parliament over allegations of lockdown-breaching bashes in Downing Street, and insisted he told the Prime Minister to get a grip on the "madhouse" when warning him over one "drinks party".
Ian Blackford, the SNP's Westminster leader, has now said that Mr Cummings was a key witness and called on the former adviser to be interviewed as part of Sue Gray's expanding probe into parties held Number 10 during England's coronavirus lockdown.
