A UK minister has been asked to explain why “as a supporter of the Union” her government excluded journalists from Scottish newspapers from a key Downing Street briefing on the Brexit trade talks.

Joanna Cherry, the SNP justice and home affairs spokeswoman, put the question to Cabinet Office minister Chloe Smith, who appeared to suggest the subject of the meeting – the EU/UK talks – was not relevant to Scottish journalists.

The exchange took place in the House of Commons yesterday after an outcry over the barring of some reporters from UK-wide media outlets from the meeting on Monday.

But it later emerged no Scottish correspondent based at Westminster was invited to the briefing arranged by the Prime Minister’s aides.

Cherry pressed Smith: “She has mentioned how important the Union is to her. I spoke to members of the Scottish lobby about this issue this morning and it is well established that the Scottish media outlets were excluded from the briefing yesterday. Will the minister clarify a very simple question – was that an oversight or was it deliberate?”

The minister replied: “I have already explained that this particular briefing was arranged to provide

further specialist briefing.”

Alison Thewliss, the SNP MP, later pressed Smith: “Can the minister tell me why she does not value Scottish media? Does she agree that is difficult to report outside the Westminster bubble if the Government do not invite Scottish journalists?”

Smith replied that “any member of the lobby with a press pass is more than welcome to put any question to the Government”.

The issue was also raised by SNP MP Pete Wishart, who said: “Yesterday was a black day for press freedom and no amount of sleekit, self-justified nonsense from the Honourable Lady is going to get her off the Trumpian hook.

“The next thing the Prime Minister will be talking about fake news and banning broadcasters, oh wait, he already has! Just how sinister can it get?”

Conservative MP James Wild (Norfolk North West), a former special adviser in Number 10, said: “There’s nothing unusual in providing specialist briefings, indeed I was there when we provided one on the Prime Minister’s excellent Brexit deal.”

He added: “Isn’t it important that we keep perspective here and in my experience, the lobby are well able to look after themselves.”

John McLellan, director of the Scottish Newspaper Society, the organisation which represents newspapers in Scotland, later hit out at the decision.

He made reference to a decision by Alex Salmond to bar some titles from a press conference following the

independence referendum.

“The Scottish Government excluded selected publications from a major press conference in 2014 and I’m very disappointed that Number 10 seems to have done the same this week. It is unacceptable for UK or Scottish governments to exclude news organisations they deem not to be favourable from official media events and I hope this will be the last time it happens.”

As the controversy entered a second day it emerged the head of the civil service has been asked to investigate the “deeply disturbing” decision to order senior journalists from London-based media to leave before

the briefing.

Cabinet Secretary Sir Mark Sedwill was told the situation – which led to a boycott by journalists who had been allowed to attend the briefing – was “damaging to democracy”.

Labour leadership hopeful Sir Keir Starmer requested the investigation into Monday’s events, saying: “Johnson’s decision to ban selected media from having access to civil service briefings damages democracy.”

Ian Murray, executive director of the Society of Editors, said there were “very real” concerns for press freedom. He said: “Yesterday’s actions are very much at odds with the pledges made for freedom of expression by the Prime Minister in his Queen’s Speech in December.”