Ministers were under growing pressure last night to order a boycott of the World Cup in Russia.

As speculation mounted about Russian involvement in the nerve agent attack in Salisbury, MPs questioned whether England’s participation in the tournament should go ahead.

Whitehall sources say it may be only a matter of days before detectives are able to confirm whether there is a Russian link to the attempted assassination of Sergei Skripal and his daughter Yulia. One MP last night described the attack as a ‘brazen act of war’.

Tom Tugendhat, chairman of the Commons foreign affairs committee, said ministers should urge allies to join a co-ordinated boycott of the World Cup, as part of a wider package of reprisals against the Putin regime. He said it was ‘extraordinary’ that the tournament was being held in a country that used ‘murder as an instrument of state policy’, and said a boycott should be ‘kept on the table’.

Whitehall sources say it may be only a matter of days before detectives are able to confirm whether there is a Russian link to the attempted assassination of Sergei Skripal and his daughter Yulia (pictured together)

Former Labour minister Chris Bryant, chairman of the all-party parliamentary Russia group, said it would be ‘very difficult’ for the England football team to compete in the event if Moscow is proved to be linked to the attack. The call came on another dramatic day in which:

■ A police officer who had been left seriously ill after coming to the aid of the Skripals was named as Detective Sergeant Nick Bailey. He remained in a serious condition last night but was said to be sitting up and talking;

■ It emerged that 21 people have needed treatment following the attack in Salisbury on Sunday;

■ There was growing concern for Mr Skripal and his daughter, who have been in intensive care since Sunday;

■ The grave of Mr Skripal’s dead wife and son were also cordoned off, while forensic tents were erected around his home;

■ Sources described the nerve agent used against them as ‘exotic’ – suggesting it was not an established chemical weapon such as sarin or VX;

■ A leading Russian state TV presenter issued a veiled threat against those thinking of following in Mr Skripal’s footsteps and helping the West, saying: ‘The profession of a traitor is one of the most dangerous in the world.’

■It emerged one of the World Cup’s major corporate sponsors was considering reducing its presence. McDonald’s UK is apparently yet to exercise an option to take child mascots to Russia this summer.

Publicly, ministers are refusing to speculate on Moscow’s involvement in what Home Secretary Amber Rudd described yesterday as an ‘outrageous crime’.

But privately they have already started drawing up a package of sanctions aimed at Putin’s regime if, as expected, the nerve agent attack on a former Russian spy and his daughter turns out to have emanated from Moscow.

Theresa May last night said the UK would ‘do what is appropriate... if it is proved to be the case that this is state-sponsored.’

Defence Secretary Gavin Williamson went further, suggesting Britain had to show it could not be ‘pushed around’ by Moscow. ‘Russia’s being assertive, Russia’s being more aggressive, and we have to change the way that we deal with it,’ he said.

Boris Johnson warned on Tuesday that British officials could boycott the World Cup if Russia is proved to be involved. Royal sources have also confirmed that Prince William will not attend the event, despite being president of the Football Association

Boris Johnson warned on Tuesday that British officials could boycott the World Cup if Russia is proved to be involved. Royal sources have also confirmed that Prince William will not attend the event, despite being president of the Football Association.

But ministers are now under pressure to go further by pressuring the FA to withdraw England from the event in June. The Government cannot order the team to pull out. But ministers could place huge pressure on the Football Association to withdraw from an event that will be used for propaganda purposes by an enemy of the UK.

Tory grandee Sir Edward Leigh last night described the attack as a ‘brazen act of war’.

Mr Tugendhat said ministers should urge allies to join a co-ordinated boycott of the World Cup.

Mr Tugendhat said he was ‘not normally in favour of mixing sport and politics’, but said the serious nature of the attack meant a boycott should be ‘kept on the table’. He added: ‘It is extraordinary that an international sporting event designed to promote peace is being held in a country that has bought it with corrupt money … while using murder as an instrument of state policy.’

Labour MP Mr Bryant likened the Russian World Cup to the notorious 1936 Olympics in Berlin, which were exploited by Adolf Hitler to promote Nazi propaganda. The former culture, media and sport spokesman said it would be ‘very difficult’ for the UK to continue with the event if Moscow is proved to be linked to the attack.

‘The World Cup shouldn’t be happening in Moscow at all because it was corruptly awarded,’ he said.

‘Putin loves using these moments to glorify Russia and he will want to do so again. It will be like 1936 all over again.’

Downing Street said that a boycott by the England team was ‘not a matter for us’.

But officials are looking at whether allies such as France, Germany, Australia and Japan might also be persuaded to withdraw their officials and dignitaries from the event, which begins in June.