The National Trust for Scotland (NTS) has announced that it will lose 91 full-time posts in 2009-10, while recruitment of new seasonal staff will be put on hold and 11 properties face full or partial closure.

Kate Mavor, chief executive of the NTS, said: "Like most organisations, the trust has been considerably affected by the recession, and we accept that we have to respond to the economic conditions by making these cost savings.

"Inevitably, this includes reducing our staffing levels and doing everything we can to ensure the charity is more efficient, if we are to have a sustainable future.

"The proposed job losses are regrettable, but as staffing accounts for 50 per cent of our operating expenditure, we must inevitably face the prospect of redundancies."

But Alan Denney, national secretary of the trade union Prospect, said he believed the depth of the cuts was a result less of the recession and more of mismanagement of the trust over several years.

"Staff morale is rock bottom and getting worse," he said. "People have a lack of confidence in the leadership team, which is persisting because they are not coming up with credible answers to our questions.

"For instance, we asked for an emergency appeal to get the NTS's finances in order, but were told that this was not appropriate. It feels as though they are intent on committing hara-kiri.

"The concern is that the cuts are so deep and extensive that they are going to take the trust to a sub-critical condition and into a rapid downhill spiral."

The NTS reported a deficit of £800,000 in September, at the time of chief executive Mark Adderley's resignation. Kate Mavor took over the role at the beginning of March.