The Prime Minister weighed in to the row over flags on Scottish food, claiming the SNP “did not want to see the Union Flag and the word British on produce”.
Documents have revealed Scottish government officials telephoned the high street giant “to seek clarity on the situation” after Scotch whisky was listed as being from the United Kingdom on its website.
A separate briefing marked “urgent” was sent to Nicola Sturgeon over Tesco’s decision to change the branding on Scottish strawberries from the Saltire to a Union Flag.
Scottish Tory MP Luke Graham raised the issue at Prime Minister’s Questions, saying: “Does she share the surprise that I had as a former M&S employee at the news that the SNP administration had bullied Marks & Spencer over the use of the word British, and the Union Flag on British produce?
“Will she stand with me against this petty bullying and support companies that are proud of Scottish and British produce?”
Mrs May replied: “Can I absolutely agree with him. We should all be proud of Scottish and British produce, of produce from any part of our United Kingdom.
“And I think it is frankly appalling that the Scottish government did not want to see the Union Flag and the word British on produce.
“It’s not only appalling, it fails to reflect the vote that took place in Scotland, which showed that people in Scotland want to stay part of the United Kingdom.”
M&S admitted it had made an “unfortunate mistake” in promoting Scottish whisky as a ‘British’ product when the row first erupted in November. A reader of the pro-independence newspaper the National wrote in to complain that the quintessentially Scottish product “only merits a listing under Great Britain” on the M&S website.
Last week, documents released to the Scottish Conservatives revealed that civil servants contacted M&S by phone, later following up to ask the retailer if it would “send any tweets (or something) to clarify the situation”.
Tory MSP Murdo Fraser accused the Scottish Government of behaving in a “parochial” manner and seeking to “berate” companies for “daring to refer to the UK”.
A Scottish Government spokesman said: “We appreciate the commitment that M&S and many other major retailers make to Scottish high quality food and drink.
“We raised concerns with the company in a constructive manner – concerns which were also being expressed by members of the public – exactly as people would expect.
“Scotland’s food and drink sector is a huge international success story and it’s vital it’s promoted appropriately.”