The Green Party was offered £250,000 to stand aside in the Richmond Park and North Kingston byelection, claims a report by three Kingston Green party members.

The money was not accepted, according to the report, after it failed to pass donation scrutiny.

The Green party did not field a candidate in the byelection where Liberal Democrat Sarah Olney unseated independent Zac Goldsmith last Thursday.

The Conservatives, Mr Goldsmith’s former party, nor UKIP stood candidates either.

The confidential report, co-authored by Ryan Coley, the chairman of the Kingston Greens, and members Clare Keogh and Kieron Merrett, claimed the national party put pressure on the local group to stand aside.

It read: “Party staff added pressure on a small group of KGP (Kingston Green Party) members by telling us that there was an offer of a large donation to the party which was conditional on the party demonstrating its desire for a ‘progressive alliance’.

“KGP members were told this could affect the jobs of party.

“There was therefore a desire for local members to comply.

“Party staff present at the meeting on November 2 informed a group of KGP activists, in confidence, that the party staff were keen for us to agree to stand down.”

The Green party said it disputes many of the claims made, insisting it has not accepted major donations connected with the Richmond Park byelection.

A party source however did confirm a staff member discussed a potential donation with local members, and that this was an “error”.

He said: “A member of staff made an error in talking about this potential donation – that shouldn’t have happened, but in the end it didn’t influence anything and the donation was rejected anyway.”

The national party added the report was an unofficial one authored by three members of the Kingston Greens, and it is not officially recognised by either the national or local party.

It also accuses the party’s joint leader, Jonathan Bartley, of warning Kingston members not to embarrass the party in the eyes of the press.

Local members allegedly received messages via social media, emails and phone calls from national executive members and party staff that pressured them to agree to stand aside.

It reads: “We believe that, in the current absence of any mandate for a national strategy for a progressive alliance, the decision of local party members should not have been directly influenced by the leadership, and Jonathan Bartley should have excused himself from the meeting on November 2.”

It also claimed the national party’s backing of Ms Olney in the national press put further pressure on them to comply.

Mr Coley, Ms Keogh and Mr Merrett were among seven Kingston Green party members to sign a letter to the Guardian in support of the Labour candidate, Christian Wolmar on November 28.