The Scottish Government is “urgently” assessing the effect north of the border of Prime Minister Rishi Sunak’s “unforgivable betrayal” in watering down climate pledges, a minister has said.

Mr Sunak said on Wednesday England would delay the move by five years, with Scotland forced to follow suit.

Mr Sunak was criticised by environmental activists, and some in his own party, following the Downing Street announcement, which also saw him push back the phasing out of petrol and diesel cars from 2030 to 2035, weaken the plan to phase out gas boilers from 2035, so households that will struggle the most to switch to heat pumps will not have to make the change, and scrap the requirement for energy efficiency upgrades to homes.

Responding to an urgent question in Holyrood, Net Zero Secretary Mairi McAllan said: “The Prime Minister’s statement yesterday was an unforgivable betrayal of current and future generations and has again put the UK on the wrong side of history.”

Ms McAllan said the Scottish Government “remained firmly committed” to its net zero targets, adding: “We have always been clear that the delivery of Scotland’s climate ambition is contingent on action by the UK Government in reserved and shared areas, and yesterday’s announcements will undoubtedly have serious implications for the delivery of climate ambition in Scotland.”

The minister said they were given no notice of the announcement from Downing Street which could have an impact on the Government’s draft climate change plan being published, adding: “We are now currently having to urgently assess the impact on Scotland and it’s right that we take the time to do that.

“But right now, however, Parliament will recognise that the sheer scale of the Prime Minister’s astonishing policy reversals will have a potentially significant impact on development in Scotland, not least on the preparation of our own draft climate change plan.”

Opposition politicians, however, criticised the Scottish Government’s failure to meet its climate change targets, with the Climate Change Committee reporting last year that it had missed seven out of 11 key targets.

Labour MSP Sarah Boyack urged the Scottish Government to back her party’s £28 billion climate plan, while Scottish Tory MSP Douglas Lumsden said climate targets had to be “realistic”, which was something accepted by the Prime Minister.

Scottish Lib Dem MSP Liam McArthur accused Mr Sunak of embarking on a “scorched earth policy”, which will make it “more difficult” for the Scottish Government to meet its climate targets.

Deputy First Minister Shona Robison said on Thursday the decision “essentially pulled the rug from under the net zero ambitions, not just of the UK, but potentially damaging the net zero ambitions of Scotland”.

She added that the shift by the PM is an attempt to appeal to the Tories’ “core vote”, adding: “Which is essentially culture wars, anti-migrants and now anti-environment.

“What an unappealing, negative, backward-looking, small-minded prospectus that is, and it will be roundly rejected by the Scottish people once again.”

The announcement comes after SNP Westminster energy spokesman Dave Doogan said the shift would be required to ensure the UK Government did not intervene using the Internal Market Act to stop substantial divergence.

He also suggested continuing to aim for 2030 would put the motor industry in Scotland at a “strategic disadvantage”.

The UK Government has been asked for comment.