Peng Shuai demonstrators at Wimbledon allege harassment by security staff

Campaigners wearing T-shirts with name of Chinese tennis player say they were told not to approach anyone

Activists wearing Where is Peng Shuai?" T-shirts claim they were confronted by Wimbledon security staff who warned them against approaching spectators and political messaging at SW19.

Nine-time champion Martina Navratilova expressed her anger at the move after the campaigners posted a video online saying they were stopped and questioned.

The group of four men from the Free Tibet campaign said they came to Wimbledon to raise a bit of awareness" about the Chinese tennis player, a former doubles world No 1.

The 36-year-old disappeared from public view for weeks last year after she made public allegations on social media saying that a former top-ranked Communist party official pressured her into having sex.

But her post was deleted quickly, and Peng was not seen for a couple of weeks. She later appeared only in photo opportunities arranged by Chinese officials. The Women's Tennis Association (WTA) suspended hosting events in China because of their concerns about her.

Will Hoyles, 39, one of the campaigners, said: We came trying to raise a bit of awareness but Wimbledon have managed to make it worse for themselves by harassing us ...

They were asking loads of questions about what we were going to do, why we were here, you know, what we'd already done etc. And we told them we'd just been wandering around and we'd spoken to a few people and that's when they seemed to get quite suspicious."