The British government is considering whether to allow Russian officials to visit Yulia Skripal, who is recovering in hospital after she was poisoned in an assassination attempt on her ex-spy father.
The demand for access to Ms Skripal came as Russia accused Britain of “blatant provocation” after border force officers searched an Aeroflot plane at Heathrow and the Kremlin ordered Britain to withdraw more than 50 diplomats from Russia.
The UK Foreign Office said it would take the 33-year-old’s “rights and wishes” into account along with international laws after receiving “requests for consular access” from Moscow.
Ms Skripal is said to be conscious and talking after the nerve agent attack in Salisbury on 4 March left her fighting for life.
The Russian embassy has said it “insists” on the right to see her after it emerged her condition was rapidly improving.
A Foreign Office spokesperson said: “We are considering requests for consular access in line with our obligations under international and domestic law, including the rights and wishes of Yulia Skripal.”
After the search of an Aeroflot plane at Heathrow, Russian officials warned they may “take similar action against British airlines” unless they receive an explanation.
The passenger jet was searched upon landing at Heathrow following a scheduled flight from Moscow, according to the Russian embassy in London.
The embassy suggested the plane had been searched in connection with the diplomatic crisis which has erupted following the Salisbury spy poisoning.
It also claimed border force and customs officers at first tried to search the plane without the crew, although the captain was eventually allowed to be present.
On Saturday, the Russian ministry of transport said in a statement: “If there is no explanation, the Russian side will deem the actions towards our plane as illegal and also reserve the right to take similar action against British airlines.”
The Metropolitan Police, which is coordinating the investigation into the poisoning of Sergei Skripal and his daughter Yulia, said it was not part of the search.
Securities minister Ben Wallace described the search as “routine”.
The Russian embassy said it had complained to its British counterparts and called for an explanation.
“We have witnessed another blatant provocation by the British authorities,” it said in a statement. “This kind of event is extraordinary. Moreover, the British officials tried to search the aircraft without the crew being present, something categorically prohibited by the rules in force.
“Our attempts to get in touch with the Foreign Office in order to clarify the reasons of the inappropriate behaviour of British officials did not bring fruit. The embassy has sent a diplomatic note demanding the British side to provide explanations of the incident.
“At this moment, we have no other explanation but that the incident at Heathrow is in one way or another connected with the hostile policy that the UK government is conducting with regard to Russia.”
The Russian embassy has published a list of 27 questions about the Skripals which it claimed had gone “unanswered” by the British government. Many of the questions addressed the medical treatment the Skripals received following the attack.
Russian officials also said they had been in contact with Mr Skripal’s niece, Viktoria, who “would like to go to London and to visit her cousin” Yulia. They called on British authorities to “issue her visa without delay” for “humanitarian reasons”.
Tory MP Bob Seely, a Kremlin expert who sits on the Foreign Affairs Select Committee, told The Independent: “I think the Russians are being bloody minded and they are making a point, but I am not quite sure what that point is, other than they are going to demand this access.
“Whether that is to unnerve [the Skripals], whether it is to play psychological games – the Russians love psychological warfare – or whether there is another angle here, I am not sure.
“But this isn’t just a standard request – they will have thought about their options.”
Asked whether the Foreign Office should be considering Russia’s request for consular access to Ms Skripal, Mr Seely, a former soldier who lived in Russia in the 1990s, said: “I would be tempted to say no until both of them are in a state, hopefully, to decide whether they want to.
“I certainly wouldn’t be granting the Russians access to the daughter without her consent. If she doesn’t want to then the answer is no.
“Otherwise I think it could be a very unnerving and unpleasant experience for her, and she’s still in a vulnerable state.”
Mr Wallace said: “It is routine for the border force to search aircraft to protect the UK from organised crime and from those who attempt to bring harmful substances like drugs or firearms into the country.
“Once these checks were carried out the plane was allowed to carry on with its onward journey.”
The Kremlin has also ordered Britain to withdraw more than 50 diplomats from Russia in retaliation for coordinated expulsions of Moscow’s diplomats by nations around the world.
Ambassadors from more than 20 nations were called into the foreign ministry in Moscow on Friday to be told of the latest wave of retaliatory measures, after dozens of countries this week banished Russian diplomats alleged to have been undeclared intelligence agents.
The UK expelled 23 Russian diplomats in the wake of the poisoning of the Skripals with a novichok nerve agent. Russia has already retaliated in kind against Britain, but said it would expel “a little over 50” in total to bring “parity” between the size of the countries’ diplomatic missions.
Laurie Bristow, the UK ambassador in Moscow, was among those called into the foreign ministry.
He told reporters: “It is important to bear in mind why this crisis has arisen in the first place.
“It’s the use of a chemical weapon on the streets of the United Kingdom that has threatened the lives of a number of people in my country. We asked certain questions of the Russian state and have still not received adequate answers.”
So far, more than 150 Russian diplomats have been told to return home by the UK’s allies.
Ms Skripal, who is a Russian citizen, spent three weeks in a critical condition after being exposed to novichok on 4 March.
Her father, a former MI6 spy, remains in a critical but stable condition in hospital.
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