BORIS Johnson has said that Ian Blackford should have "more optimism" when questioning him on Covid rules.

The PM made the comment after Blackford, the SNP's Westminster leader, praised the UK's vaccine rollout.

Speaking in the Commons, he said: "The success of the vaccine rollout, led by our incredible NHS staff, was something to behold and something that we are all thankful for. For the first time in many months across these islands people are genuinely hopeful that an end to the current level of lockdown is finally in sight."

But Blackford went on to talk about the different quarantine rules for international travellers in Scotland and England.

Since Monday, travellers from any country arriving in Scotland will be forced to self-isolate in a hotel for 10 days on arrival.

In England, only travellers arriving from so-called “red list” countries will need to quarantine, which means someone flying in from elsewhere could land in England and then cross the border into Scotland themselves without the need to self-isolate – and avoiding the £1750 hotel accommodation fee that goes with it.

Blackford added: "People also know that there is one major threat that could undo much of this hope. The spread of new international variants of this virus now poses the single biggest threat to finally getting out of this pandemic – that is why quarantine measures for international arrivals is so important. We simply can't afford to get this wrong and that is why the Scottish Government has taken tough but absolutely necessary action.

"Those arriving in Scotland on an international flight have to quarantine in a hotel for 10 days. In England though the policy only applies to those travelling from red-list countries. But the evidence shows that people across the UK are supporting stronger measures to prevent the threat of any new variant."

READ MORE: UK's ‘red list’ quarantine system undermines efforts to keep Scots safe

He went on to say that a YouGov poll last week showed that only 18% supported the UK's rules on quarantine, while 72% of people prefer the Scottish Government's approach.

"Prime Minister, your plan to end lockdown will be worthless if your insufficient quarantine measures allow a new variant in through the back door," Blackford added.

"People across the UK are continuing to make huge sacrificies, children are not yet in school, families, are isolated because there is a loneliness epidemic. People are really struggling and this can't be all for nothing. Do not leave the back door open, do not risk all the hard work, all the sacrifices that have been made.

"Given all that is at stake, can you explain why the UK Government is failing to introduce the strong quarantine meaures that the public across the UK are demanding. Will the Prime Minister think again and introduce the Scottish Government's comprehensive approach for international travellers?"

Johnson responded: "We have the toughest quarantine measures anywhere in the world as the right honourable gentleman well knows, including the mandatory incarceration in hotels appointed by the government if you return from one of the 33 red list countries as he well knows and we will continue to impose very very tough controls on people coming into this country.

"He should also know that the new variants are ... we are confident that all our vaccines are effective in reducing death and serious disease and we have no reason to doubt they are efeective in reducing death and serious disease with the new variants as well Mr Speaker. He should also know that over the course of the next few months we will see new vaccines to defeat these vaccine-escaping variants and that is something that is evolving.

"Other than that, Mr Speaker, I was delighted at the unaccustomed note of optimism by which the right honourable gentleman began. He is not notable for his optimism in this house."

The camera then cuts to Ian Blackford shaking his head.

"He's rolling his eyes, Mr Speaker," Johnson went on. "I rather liked it when he began with optimism. I think he should stick to it. I think it suits him. More optimism I think from the right honourable gentleman would be nice to hear."