A woman accused of "political interference activities" in the UK on behalf of the Chinese Communist Party denied the claims on Tuesday as part of her legal claim against intelligence services.
Domestic intelligence service MI5 warned in 2022 that Christine Lee was a Chinese agent who had engaged with members of parliament after she donated £500,000 ($635,000) to Labour MP Barry Gardiner.
Lee is now suing the security services, and on Tuesday told a hearing that she was used as a "political football" and that she "categorically denied" the claims.
She also alleged that she had been discriminated against "on the grounds of my race".
The Security Service submitted to the two-day hearing that the decision was "rational and lawful".
"Ms Lee's race and/or nationality played no part in the decision to issue an interference alert," said Victoria Wakefield, lawyer for the Security Service.
"As noted, the decision was made on grounds of national security in order to counter the threat posed by Ms Lee's links to the CCP," she added.
The hearing is expected to end on Tuesday, with a decision due at a later date.