The BBC has upgraded security practices after staff received an influx of death threats and a presenter was harangued by conspiracy theorists.

Footage emerged on Tuesday of Nicholas Watts, Newsnight’s political editor, rushing hurriedly through an aggressive mob of anti-vaccination protestors who accused him of "lying" about lockdowns.

Since then, other journalists and staff at the broadcaster have received death threats from people who believe that the pandemic is fabricated and that vaccinations are a means of Government control.

The influx of threatening behaviour has prompted the BBC to offer training on how to deal with an "in-person attack" and to set up a working group for anyone affected by the abuse.

Many of the threats have been via the unregulated social media platform Telegram.

In messages seen by The Observer, comments from known conspiracy theorists expressed wishes to see BBC journalists dead and exchanged their contact information.

One individual, writing about the incident with Nicholas Watts, said "I hope he gets killed", while another responded: "If the police weren’t there, he could and should have been lynched."

On the same thread, another follower wrote: "I hope people track him down."

Fran Unsworth, director of news and current affairs, sent a message to staff on Friday which acknowledged the "growing problem" of the "abuse of journalists". She said that women and ethnic minority reporters were the particular focus of the abuse. 

"We know these attacks are more often aimed at women and journalists of colour, so we want to make sure we have particular support for those groups and are looking at what this could be," she said. 

Imran Ahmed, chief executive of the Centre for Countering Digital Hate, told the Observer that anti-vaxxers had gone beyond spreading misinformation to the tactics of intimidation.

He said: "They have sought to spread fear among those spreading good information on Covid by directing their supporters to troll and abuse them. This organised trolling has continued unabated despite repeated warnings to social media bosses."