Kilmarnock have hastened the departure of manager Allan Johnston less than 24 hours after he announced his intention to quit in the summer.

The Kilmarnock board met on Thursday night following Johnston's shock revelation at his weekly media conference and decided he should depart Rugby Park immediately.

A club statement read: "Allan will stand down as manager with immediate effect and the board has therefore appointed assistant manager Gary Locke as interim manager pending a permanent appointment."

Johnston surprised the board with his announcement on Thursday lunchtime and indicated the manner of Robbie Muirhead's sale to Dundee United late on transfer deadline day had been the final straw.

The full club statement read: "The board of directors would like to express its thanks to Allan Johnston for his diligent service over the last 18 months.

"Allan kept the club in the Premiership last season by recording crucial end of season victories and an excellent start to the current league season raised expectations.

"Unfortunately, a number of injuries to key players and a series of poor results followed and although the club sits in eighth place in the Premiership, Allan decided to announce his decision to leave the club to the media on Thursday."

The club revealed that Alan Robertson would provide support as former Hearts manager Locke's assistant.

The statement finished: "Applications for the post of manager are invited and will be considered by the board over the coming weeks."

Killie sit six points outside the top six with a game in hand, which comes at Hamilton on Saturday, but a run of two wins from 14 games had seen many fans turn against their former player.

But their position is an improvement on last season when they only avoided a relegation play-off with a 1-0 victory at Hibernian on the final day of the league season, thanks to Kris Boyd's 22nd goal of the campaign.

Boyd returned to Rangers in the summer but Kilmarnock made a good start to the season and it has been off-field issues that have sparked Johnston's departure.

Muirhead was sold moments before the transfer window closed and Johnston was not allowed to bring in a replacement when he asked chairman Michael Johnston.

When explaining his decision on Thursday, Johnston said: "There is a number of things but that certainly doesn't make your job any easier.

"I never found out Robbie was away until five past 12. Stuff like that, it is not the way things are done.

"It was very disappointing. Especially when you see a lack of goals this season.

"I spoke to the chairman and told him that if Robbie left we would only have one fit striker because Michael Ngoo is out for the rest of the season and Lee Miller is a few weeks away.

"I said that we definitely needed to bring another striker in to strengthen the squad.

"He said that even if Robbie left then we were not in a position to do that."

Johnston had announced his decision by saying: "There is a new chairman (Jim Mann) coming in and I think it is important that there is a freshness about the club and it is time to move on anyway. Until then I will give 110 per cent."