SINGAPORE - The former Progress Singapore Party (PSP) member who made allegations that the party had been infiltrated by foreign proxies has made a written apology to Singapore People's Party chairman Jose Raymond.

Mr Daniel Teo, 36, who works in a marine infrastructure firm, had claimed in an anonymous video last month that 10 members of the PSP were working with Mr Raymond and historian Thum Ping Tjin while "funded by Western liberal sources".

He was expelled on May 1 after admitting to PSP secretary-general Tan Cheng Bock that he was behind the video.

A letter of demand seeking an apology and damages was served on Mr Teo on Sunday (May 3) by Mr Raymond's lawyer.

In a Facebook post on Tuesday evening, Mr Teo wrote: "I admit and acknowledge that these allegations are false and completely without foundation and I unreservedly withdraw them.

"I unreservedly apologise to Mr Jose Raymond for the distress and embarrassment caused to him by these false allegations. I undertake not to make any further allegations to the same or similar effect."

The apology will have to remain public for at least a year, and Mr Teo would have to make a donation to The Straits Times School Pocket Money Fund for an amount equivalent to the sum required for publishing an apology in The Straits Times, Mr Raymond's lawyer Eugene Thuraisingam instructed Mr Teo's lawyers on Tuesday.

The damages Mr Raymond initially demanded will also be waived as a gesture of goodwill, after Mr Teo's lawyers at Goh JP & Wong LLC said in a letter that their client earns "mediocre wages" and does not have the means to pay any damages.

Mr Teo's lawyers also explained that he is "deeply sorry and remorseful for having acted in such a rash manner", and that he had made the video on the spur of the moment after hearing the allegations from various sources of his own.

"It was never our client's intention to defame or harm anyone, or anyone's reputation for that matter. Our client had never intended to publish this video without properly checking the veracity of its allegations and contents."

Mr Teo's lawyers said he had sent the video to a Today reporter to fact-check the allegations, and that he believes it was leaked to the mainstream media or on the Internet by someone who had access to it after the reporter had sent it to PSP for comment.

However, in a Today article published on Tuesday, the reporter said the allegation was "completely false" and that at no point was she asked by Mr Teo to fact-check any video.