Chinese officials were “concerned” Boris Johnson did not send a personal message of support after the coronavirus outbreak, emails suggest.
The PM’s father, Stanley Johnson, met Chinese ambassador Liu Xiaoming and emailed his worries to UK officials – accidentally copying in the BBC.
Mr Liu told him the prime minister had not yet directly contacted the Chinese.
A government spokesman said the UK had been in close contact with the Chinese authorities since the outbreak.
Sources also stressed Stanley Johnson was not acting on behalf or at the request of the British government.
Stanley Johnson held a 90-minute meeting with Mr Liu on Tuesday.
Mr Johnson, a longstanding environmental campaigner, was invited to the Chinese embassy to discuss summits on the topic, due to take place this autumn in China and the UK.
Shortly after the meeting, the PM’s father used his personal email address to share an account of the discussion with the environment minister Lord Goldsmith and other UK officials.
He wrote: “Re the outbreak of coronavirus, Mr Liu obviously was concerned that there had not yet – so he asserted – been direct contact between the PM and Chinese head of state or government in terms of a personal message or telephone call.”
Stanley Johnson also revealed he had raised the possibility of his son visiting China in October to attend an international conference on biodiversity, COP15, which will be held in Kunming.
Lord Goldsmith wrote a reply from his personal email address saying: “Thank you so much Stanley. That is extremely useful.”
No one in the exchange appeared to have noticed the BBC was copied in until it was raised with them.
Mr Liu later shared pictures of him and Stanley Johnson on Twitter, saying they met to exchange views on the COP15 meeting and the COP26 meeting on climate change, to be hosted in Glasgow.
He added: “These two conferences are great opportunities to promote international cooperation on environmental protection & climate change.”
A UK government spokesman said: “The government has been in close contact with the Chinese authorities since the start of the outbreak.”
The foreign secretary and national security adviser had spoken to their counterparts in the past week, the spokesman added.
“The UK has provided medical supplies to help China tackle the outbreak and together we have facilitated the repatriation of British nationals and their dependants from Wuhan,” he said.