Questions have been raised about Chief Constable Sir Stephen House's public absence during the controversies that have engulfed Police Scotland after the police watchdog confirmed he has been keeping "a lower personal profile" ahead of his imminent resignation.

Sir Stephen was absent at a Scottish Police Authority (SPA) meeting which revealed Police Scotland's budget gap has more than doubled to £25 million due to "alternative diary commitments", SPA chairman Larry Flanagan said.

He did not comment on a staff survey which revealed a third of personnel plan to leave Police Scotland, an HM Inspectorate of Constabulary (HMICS) report into control-room failures following the death of a couple on the M9 and Aberdeen Council's outrage at the merger of two northern divisions.

Sir Stephen also missed a number of public engagements as well as not commenting on a Holyrood committee's criticism of stop and search and a domestic abuse disclosure scheme.

Mr Flanagan said Sir Stephen's public absence would not be "overly surprising" to anyone after he announced his decision to step down on December 1, nine months before his four-year contract expires.

However, he said Sir Stephen will continue to fulfil his obligations of command until his successor is appointed in the coming weeks.

Liberal Democrat leader Willie Rennie, a critic of the merger which put Scottish police under the command of a single chief constable, said Sir Stephen's absence "is just not good enough".

In a letter to Mr Rennie, Mr Flanagan said: "There have been no changes to the command arrangements in place within Police Scotland.

"Sir Stephen House remains active as Chief Constable and will continue to fulfil that command position until he steps down at the turn of the month.

"He has a designated deputy in Deputy Chief Constable Neil Richardson who is available to deputise for the Chief Constable, for example through periods of leave.

"That arrangement has been in place since the inception of the single service nearly three years ago."

He added: "Since his personal decision to stand down, the Chief Constable has in the intervening period had a lower personal profile.

"I do not believe that is an overly surprising outcome to anyone in Scotland.

"Nor do I think it is unusual for other members of the Police Scotland leadership team to take a presentational lead on specific issues as they arise."

Sir Stephen missed the SPA meeting which uncovered the force's spiralling budget gap on October 27 due to "alternative Police Scotland diary commitments which prevented him attending", he said.

Mr Rennie said: "Given the seriousness of the matter I can't imagine what other commitments could have been more important.

"It's just not good enough and it doesn't end there. The Chief Constable was nowhere to be seen during a series of critical reports on his flagship policies, including the HMICS review of call handling and control room closures following the M9 tragedy.

"I'll ask again: where is the Chief Constable?"