KEIR RADNEDGE REPORTING —- Boris Johnson, the UK’s loose cannon of a Foreign Secretary, sparked diplomatic and sporting panic when he appeared to suggest that England would be pulled out of the World Cup following the so-far unexplained poisoning of a former double agent.

The Foreign Office later rushed out a statement saying Johnson meant only a political presence at the finals in Russia in June and July and not the manager Gareth Southgate and his national team but by then it was too late.

Emily Thornberry, the Labour Party’s Shadow Foreign Secretary, mocked Johnson and his staff for the backtrack, football pundit Gary Neville derided Johnson as a “useless fool”, travel industry spokesmen warned of the harm done to their industry and a Russian Embassy described the comments as “wild.”

Boris Johnson: UK government's Foreign Minister

Johnson was making a parliamentary statement after Sergei Skripal and his daughter Yulia were discovered seriously ill on a park bench in Salisbury at the weekend in what was compared with the death in London in 2006 of former Soviet spy Alexander Litvinenko.

Johnson told the Commons the British government would take “whatever measures we deem necessary” to “protect the lives of people in our country, our values and our freedom”.

Retaliation threat

He was not yet “pointing figures”, but added “no attempt to take innocent life on UK soil will go unsanctioned or unpunished”.

Johnson described the incident as showing “that Russia is now a malign and destructive force” and said it was time to “bring Russia to heel”.

He continued: “If things turn out to be as many members suspect that they are I think we will have to have a serious conversation about our engagement with Russia.

“For my own part, I think it will be very difficult to see how, thinking ahead to the World Cup this July, this summer, I think it would be difficult to imagine that UK representation at that event could go ahead in the normal way. We will certainly have to consider that.”

The Skripals’ relatives have told the BBC Russian Service that the former spy believed the Russian special services might come after him at any time. His wife, elder brother and his son have died in the past two years, some in mysterious circumstances, the family believe.

Yulia Skripal is based in Moscow and has visited her father in the UK regularly, especially over the past two years.

She and her father were found slumped on a bench outside a shopping centre on Sunday afternoon. Earlier they were seen walking through an alley leading from a Zizzi restaurant, which has now been “secured” by police. A local public house has also been cordoned off as a precaution.

Scientists at Porton Down – the UK’s secret weapons research facility in Wiltshire – are studying the “unknown substance” that is thought to have made the pair ill.