The BBC previously said the pieces would feature without lyrics, following controversy over their perceived historical links with colonialism and slavery, but they will now be performed by a select group of vocalists.
Mr Blackford condemned the “violation” of Mr Johnson’s privacy but added a “senior Conservative source in Downing Street” was reported to have said the “finger of blame for all this getting out is being pointed at the SNP, particularly Ian Blackford who is local”.
The prime minister insisted his Government has not been blown off course by Covid-19 - but acknowledged that “sometimes it is necessary” to change direction in “response to the facts as they change”.
The newly-created profile lists the PM’s previous jobs in politics such as Foreign Secretary and Mayor of London, but does not include his previous work as a journalist.
“We’d like to be in a Government that has the impression of being competent – rather than lurching from one issue to another and then after a short time doing a U-turn.”
Sir Charles Walker, deputy of the 1922 committee of Conservative backbenchers, said it was becoming increasingly difficult for MPs to defend the government - as policies can be quickly dropped by ministers.
A senior member of staff said workers are struggling so much on their current pay that some take the night bus to work because they cannot afford the tube.
Labour accused Johnson of trying to shirk responsibility for a “shambles” caused by the “incompetence” of his government.
He also referred to the “supine stem of confiteor” and touched on the debate around whether Harry Potter is sexist or not.