A probe into undercover policing in England and Wales is doomed "to fail before it begins" after the UK Government confirmed its remit will not extend to Scotland, inquiry participants have warned.

Fifteen people who have been called to give evidence to the Pitchford Inquiry into undercover policing in England and Wales say the decision is "a snub to Scotland".

The Scottish Government, which has been urged to launch its own inquiry, said it "will now consider how best to take this matter forward".

Pitchford, set up by Prime Minister Theresa May in one of her final acts as home secretary, follows revelations about the activities of undercover officer Mark Kennedy, who admitted having "intimate relationships with a number of people while undercover".

The London-based National Public Order Intelligence Unit worked with forces in Scotland and Mr Kennedy was used in or visited Scotland 14 times, a review by HM Inspector of Constabulary (HMIC) found.

However, Policing Minister Brandon Lewis has now confirmed that Pitchford's terms of reference apply solely to "undercover police operations conducted by English and Welsh police forces in England and Wales".

In a letter to Labour MSP Neil Findlay, he said: "For a number of reasons, it is not possible to expand the geographical scope of the inquiry without formally amending the terms of reference."

The inquiry could be accused of "acting outside of its powers" if it considered evidence outside of these jurisdictions, Mr Lewis said.

Lord Justice Pitchford has granted "core participant" status to 199 people affected by the undercover police units, including some who say they were spied on in Scotland.

In a joint statement, 15 participants said disregarding evidence from Scotland will "prevent the inquiry from dealing with a significant part of its remit" and "sets the inquiry up to fail before it begins".

Participant Merrick Cork said: "The police admit English officers committed human rights abuses against citizens on Scottish soil.

"It's absurd to expect public trust in police when abuses of power are swept under the carpet, and it's a snub to Scotland to say it doesn't matter there."

The participants have called on the Scottish Government to set up its own independent inquiry.

A Scottish Government spokesman said: "The Scottish Government is extremely disappointed that the UK Government has indicated it will not extend the remit of the Pitchford Inquiry to consider the activities of undercover Metropolitan Police units in Scotland.

"We continue to believe that a single inquiry across the UK is the most effective approach to provide a comprehensive and coherent investigation into these matters.

"This narrower approach risks doing a disservice to people in Scotland affected by the activities of a force which falls under the oversight of the Home Office. We will now consider how best to take this matter forward."

Mr Lewis has said Pitchford will be restricted from forwarding its evidence on to other organisations during its deliberations, unless it uncovers a crime or miscarriage of justice.

However, he said all of the material will be lodged with the National Archives once the inquiry has concluded.