The people of the north east "deserve answers" after a Tory MSP quit his front bench post over a lobbying scandal, Labour has said.

North east MSP Peter Chapman resigned his position as Ruth Davidson's rural affairs spokesman after he failed to mention holding 50,000 shares in a firm when he lobbied councillors about a planning application.

He asked councillors to support an application by Aberdeen and Northern Marts (ANM) Group to expand their site in Inverurie.

Chapman, a local farmer in the area, owns 50,000 shares in the group, but insisted he would not stand to gain if the expansion does get the go ahead.

However, he accepted he had failed to declare his interest while lobbying local officials and apologised for the "foolish oversight".

Davidson said she accepted Chapman's resignation from her top team "with regret".

But Scottish Labour, the SNP and the Scottish Greens all slammed the Conservatives for its MSPs' "long registers of interests", telling Ruth Davidson to "clean up" her party.

Labour's rural affairs spokesman Colin Smyth said: "Ruth Davidson's band of Tory MSPs are well known for their long registers of interests - and she must be furious with him over this latest revelation.

"Rather than holding the SNP to account, the Tories seem more concerned with intervening in local issues to further their own interests.

"The public deserve to know how this situation came about, who knew about it and when - and whether any other Tory MSPs have been engaging in similar behaviour on other issues.

"People in the north-east and across Scotland deserve answers."

SNP MSP Stewart Stevenson said: "The time has now come for Ruth Davidson to clean up her party. She really needs to get a grip of her self-interested colleagues on the Tory benches.

"The Tories think that they can do what they want and get away with it - but time and time again they get caught out. Peter Chapman is not the first, and I doubt he'll be the last.

"This latest example is an incredibly serious issue and shows just how far Ruth Davidson's party are prepared to go in order to feather their own nests.

"Peter Chapman joins his Tory colleagues in doing what he can as an MSP to put the interests of his business ahead of those of his constituents' - and it's not on."

A spokesman for the Scottish Greens added: "It's no surprise that a Tory has been found lobbying without declaring his financial interests, instead of serving his constituents.

"The party of landed wealth, cruel social policies and contempt for the Scottish Parliament is full of people who view being an MSP as a hobby rather than public service.

"No amount of shuffling of Ruth Davidson's pack will change that fact."

Announcing his resignation, Chapman said: "It's quite clear with hindsight that I should have made my financial interest in the phone calls clear and that it was a foolish oversight on my behalf not to do so.

"I failed to maintain the high standards of transparency that is expected of MSPs.

"As a result, I cannot in all conscience continue in post, hence my reason for offering my resignation."

He added: "It was not my intention to hide this - indeed anyone can see the details of my investment on the Scottish Parliament register of interests.

"I can say hand on heart that my only thought was to support a local business and improve our local economy.

"I deeply regret this incident and I only hope people will see if for what it is: an honest mistake taken while trying to help my local constituents and the Aberdeenshire economy."

Davidson commented: "I know your strong commitment in all things is to your constituents in the north-east, and that you will continue to serve them with vigour over the months and years ahead."

It is not the first time Chapman and other Conservative MSPs have faced ethical concerns over their dealings.

Chapman was previously accused of selling access after raffling off a lunch in parliament for a Tory fundraiser.

Last year, Tory MSP Alexander Burnett was reprimanded and sanctioned by Holyrood's standards committee for separate incidents where he failed to declare relevant interests.

Finlay Carson, MSP for Galloway and West Dumfries, was referred to a watchdog when he hired his own IT firm to design his website then claimed the costs back from the taxpayer.

Ettrick, Roxburgh and Berwickshire MSP Rachael Hamilton also came under fire in 2016 for using her position to complain about hotel rates rises.

This was despite the fact that she was director and company secretary of the Buccleuch Arms and benefited from rates relief for the hospitality sector introduced by the Scottish Government.