A Labour donor has been accused by a local authority chief executive of threatening to coerce his council into selling a lucrative piece of land.

Developer James Kean allegedly told South Lanarkshire council officials that, unless the site was sold to his charity, he would use information he had to ensure that "people were not re-elected".

The charity's legal representative described the claims as "preposterous" and asked the council to withdraw the allegation.

Kean is an East Kilbride-based businessman whose firms have made donations to the Labour party.

In 2011, his association with local Labour MP Michael McCann was the subject of a BBC Scotland investigation.

It was alleged that McCann, when serving on South Lanarkshire Council, did not declare his ties with Kean when dealing with planning issues relating to the tycoon.

Both McCann and Keane denied any wrongdoing.

Kean is at the centre of another controversy with the Labour-controlled council, this time involving the East Kilbride Community Trust (EKCT), of which he is a trustee and major funder.

This newspaper revealed last year that the EKCT wanted to buy council land in the Langlands area of the town for £175,000 in order to build a sports arena.

McCann offered the "magnificent project" his support but the council declined due to the offer being below market rate.

Emails, volunteered to this newspaper by the Trust, reveal an extraordinary row between the charity's legal representative Stuart Chalmers and council chief executive Lindsay Freeland on the land talks.

Kean and Chalmers met senior council officers about the issue in June last year, a meeting the local authority's head of administration and legal services Geraldine McCann also attended.

Ms McCann also serves as the council's Monitoring Officer, whose job is to raise issues of concern with the chief executive.

Eight days after the meeting, the council chief executive emailed Chalmers:

"As you know, the Council's Monitoring Officer was in attendance at the meeting and she has provided me with an update of the meeting and raised some concerns regarding statements made during the meeting.

"I understand that your client referred to a 'trump card which he had up his sleeve' information which he held and was prepared to use if the Council did not agree to sell the land to him."

Freeland continued: "This could be interpreted to be a threat to coerce the Council to undertake a particular course of action. I note that your client did not provide any detail of the nature of this information other than that he was 'prepared to use it to ensure that people were not re-elected'."

"If your client is implying that any officer or elected member has acted with impropriety, then I would be obliged if you would provide me with more detail of the nature of the alleged information to allow me to take the appropriate action."

Chalmers responded: "The Trustees...have asked me to convey their deepest concern about the language of your second paragraph.

"The suggestion that any words said by Mr Kean 'could be interpreted as a threat to coerce the Council to undertake a particular course of action' is an extremely serious one. In view of the nature of this comment the Trustees require that it is withdrawn. The Trustees also require a copy of the note of the meeting taken by the Monitoring Officer.

"Mr Kean also wishes to put on record that he did not use the phrase 'prepared to use it to ensure that people were not re-elected'. He did make a reference to the next Council election and it is his recollection that the words used were quite clearly stating his wish that his dealings with the Council would hopefully improve if a new batch of Councillors were to be elected at that time."

However, the chief executive supported the Monitoring Officer in another email to Chalmers:

"I note your interpretation of the comments made by Mr Kean at the meeting. However, having discussed the matter with the Council's Monitoring Officer, she has confirmed, to me, her interpretation and I am therefore not prepared to withdraw the comments to which you object to in the second paragraph of your email.

"The Council's Monitoring Officer has confirmed to me that the statement was made, and in her opinion, could be interpreted in the way set out in my email of 24 June 2014."

"The Council's Monitoring Officer prepared a note of the meeting. The note is confidential and I am unable to provide you with a copy."

Chalmers responded by again disputing the "preposterous" claim:

"Apart from the quantum leap required to attribute anything threatening to those particular words, how can a "Council" (a non person), feel threatened?"

"The Trustees reiterate their request that you withdraw your suggestion of a threat or a perceived threat to the Council."

He added: "The Council's shortcomings in its dealings with the Trust constitute a disgrace which the people of East Kilbride deserve to know about, and no doubt they will soon enough."

The land deal was not agreed, but the council voted to enter negotiations about granting the charity a right of access through the Langlands site to develop other land under the EKCT's control.

It is understood the dispute regarding Kean's alleged statements remains unresolved.

A spokesperson for the council: "It would not be appropriate to discuss conversations in meetings that are commercially sensitive."

Asked to comment on the row, Chalmers said: "It's all in the emails. It's there for you to see, and we are quite happy for these to be quoted, as long as they are quoted fairly."

An SNP spokesperson said: "There is no absolutely place for threats in Scottish politics - Labour must confirm that any donations given by Mr Kean for the general election campaign have been returned immediately while this matter is fully investigated."

Sc��ottish Conservative MSP Alex Johnstone said: "This is typical of the murky world of Lanarkshire Labour. You'd think lessons had been learned after the Falkirk fiasco, but Labour is a party that never learns."