British officers identify key suspects in poisoning of Russian ex-spy: report

But Polish state broadcaster TVP said ex-London Police officer David Videcette was sceptical of the British paper's report.

According to the Telegraph, police searched flight records and footage from security cameras in Salisbury and are "building a case against 'persons of interest' who are believed to be back in Russia".

But TVP cited Videcette as saying that evidence that Russians were on board flights and in Salisbury does not mean they had anything to do with the attack.

On March 4, Sergei Skripal and his daughter Yulia, who was visiting from Russia, were targeted in a suspected nerve agent attack.

London said the substance was Russian-made novichok and British Prime Minister Theresa May blamed Moscow for the attack.

But Moscow denied the claim, accusing the UK of stirring up anti-Russian hysteria.

The UK expelled 23 Russian diplomats and a number of Western countries followed suit, including Poland. Russia reciprocated, expelling dozens of foreign diplomats.

Sergei Skripal remains in hospital. His daughter was discharged from hospital about two weeks ago. (vb)

Source: IAR, the Telegraph, TVP