MSPs were evacuated from their block in the Scottish Parliament yesterday morning after a suspicious white powder was found in an envelope sent to a Conservative politician.

Dozens of members and their staff were told to leave their offices while police, fire fighters and the ambulance service attended the scene.

However, Police Scotland later gave the all-clear after it emerged the envelope contained an invitation for Jamie Halco Johnstone to celebrate the 200th anniversary of a regional newspaper in the Highlands.

Two identical letters sent to two other Tory MSPs did not contain any powder.

No details about the powder have been officially released but a Holyrood spokesman said the incident affected the MSPs’ area of the building, which was cleared of all members and their staff as a precaution.

Edward Mountain, one of the three Conservative MSPs to receive the letters, said there was no white powder in his envelope. The other invitation is reported to have gone to Liz Smith, an MSP for the Mid Scotland and Fife region.

“The guy in Jamie’s office opened [the letter to Halco Johnstone] and his fingers were covered in a white powder when he did it,” Mountain told as newspaper as he spoke to ambulance crews outside Holyrood. “Unfortunately by the time he came to tell us not to open it I had already opened the invitation we had received,” he added.

“There was nothing in my invitation apart from the invitation, as it were, so we have been asked out because it is the same package that has been received by Jamie.”

Mountain, like Halco Johnstone an MSP for the Highlands and Islands region, said the invitation was to a Highland Council event to mark the Inverness Courier’s 200-year anniversary.

He said he was not worried about his own safety. “I actually think that given the people around us we’ve got no need to be nervous. I have been a soldier for 12 years, faced worse than this. This is just good hands, get on with it,” he said.

After the emergency services arrived at the scene, the office space occupied by more than 100 members and their staff was closed.

In a series of tweets during the incident, journalist Andy Philip said: “MSPs evacuated from Holyrood offices after ‘white powder’ package opened in Tory Jamie Halcro Johnston’s office.

“Another Tory, Edward Mountain, targeted but package not opened. Both are Highlands MSPs.”

He added: “A third package found in Tory MSP Liz Smith’s office. Police and fire officers cleared all floors of the office block.”

A meeting of Holyrood’s Justice Committee, held in a different part of the building, continued while emergency services investigated. Shortly after 1pm a police cordon at the entrance to the members’ tower was lifted and MSPs and their staff allowed to return to their offices.

A statement from the Scottish Parliament said: “Following this morning’s security alert you may wish to know that Police Scotland’s inquiries have concluded that there are no suspicious circumstances surrounding the incident and no crime was committed. While all of the packages turned out to be entirely benign, raising the alarm was entirely the right thing to do.”

A spokeswoman for Police Scotland confirmed the alarm had been raised at about 11.35am.

“The MSP block was evacuated as a precaution, but inquiries have concluded there are no suspicious circumstances surrounding this incident and no crime has been committed,” she said.

“Normal service at the Scottish Parliament has resumed and the block is once again opened.”