LONDON, England: A rare warning by the UK's MI5 intelligence agency has revealed that a Chinese agent, Christine Ching Kui Lee, has infiltrated Parliament to interfere in UK politics.

The warning has caused a stir among current and aspiring MPs, especially those who received donations from her.

Lee is accused of having "established links" for the Chinese Communist Party (CCP) with MPs by giving donations to politicians, with funding coming from foreign nationals in China and Hong Kong.

The charges comes after a "significant, long-running" investigation by MI5, Whitehall sources told the BBC.

One of the MPs funded by Lee was Labour's Barry Gardiner, who received over £420,000 from her in five years - though he said he had always made the security services aware of the donations.

Liberal Democrat leader Sir Ed Davey also received a £5,000 donation when he was energy secretary - but he said the money was accepted by his local association and it was "the first time he has been given cause to be concerned."

The security service said that those contacted by Lee should be "mindful of her affiliation" and its "remit to advance the CCP's agenda".

Meanwhile, Labour's shadow home secretary Yvette Cooper said Labour was seeking further information from the Home Office and MI5 on the "extent of the deception and interference and the ongoing risks of malign activity from foreign states."

Conservative MP and former party leader, Sir Iain Duncan Smith, spoke of the alert in the Commons, saying it was "a matter of grave concern," calling for Lee to be deported and demanding that the government make a statement to the House.

According to the alert, Lee claimed her involvement with Parliament had been to "represent the UK Chinese and increase diversity."

But MI5 said Lee's activity "had been undertaken in covert coordination with the United Front Work Department of the CCP, with funding provided by foreign nationals located in China and Hong Kong".

The UFWD is alleged to be seeking to "cultivate relations" with "influential figures" to ensure the UK political landscape is favourable to the CCP and to challenge those that raise concerns about the party, including over human rights.

But they warned that Lee "may aspire to establish APPGs [parliamentary groups] to further the CCP's agenda".