The founder of leading Scottish publisher Mainstream has explained his decision to close the imprint.

Bill Campbell formed the Edinburgh-based company, a leading non-fiction publisher, in 1978 with Peter MacKenzie.

On Thursday last week they told staff Mainstream will not publish new works from March next year, and 10 jobs would go. The news shocked Scotland's literary circles.

Mr Campbell said he will now pursue other business and literary ambitions, although he could not elaborate on them at the moment.

He said he did not like the idea of selling the publisher, part-owned by Random House, to another business.

Mr Campbell added: "It is not something we had to do, it is a prepared and planned exit.

"It's not the case that the company had to close, it is just that after 35, and 36 years when we are finished, of publishing, we want to pursue other things, although we are very proud of what we have done.

"It is a decision Pete and I took, and we have been mulling it over for a while.

"The idea of selling it to an outside buyer? Maybe, but we didn't want to do that. We wanted it to be on our terms.We wanted to go out together after all these years.

"Hopefully we have made our mark in the cultural history of Scotland. It's a planned exit, I have other things that I want to pursue."

Books published by Mainstream over the years have won, or been nominated for, a series of awards.

These include Duncan Macmillan's key art text, Scottish Art 1460-1990, which won the Saltire Society Best Book of the Year award in 1992; Dark Trade by Donald McRae, which was named the Sports Book of the Year in 1996; and Dreams of Exile by Herald columnist Ian Bell, which won the Saltire Society Best First Book in 1994.

It has also published books by former prime minister Gordon Brown, including his selected speeches and his biography of Glasgow socialist politician James Maxton.

Mainstream's final book will be published in March 2014.

Mr Campbell added: "It has been very rewarding to see some of the comments made: it has brought a tear to my eye."