An event at the Telegraph’s central London office was abandoned last night after three people reportedly collapsed.
According to The Drum, police were called to a question and answer session with jockey AP McCoy.
Attendees reportedly waited for an hour to exit as the area was checked for dangerous chemicals.
Ben Clerkin, The Daily Telegraph’s assistant news editor, tweeted that police were wearing "chemical warfare suits". But he later said the three guests had been left “feeling nauseous” after food poisoning.
A Telegraph Media Group spokesperson said: "Emergency services were called last night to investigate a suspected hazard in Buckingham Palace Road. Normal cautionary procedures were followed and no further action was deemed necessary."