Rhondda MP Chris Bryant - who chairs the all-party Parliamentary group on Russia - has claimed police have been under pressure not to investigate deaths in the UK linked to Russian intelligence.

His comments follow the collapse in mysterious circumstances of former spy Sergei Skripal at a shopping centre in Salisbury, Wiltshire.

Foreign Secretary Boris Johnson said the UK government would respond "appropriately and robustly" if the Russian state was found to be involved, although the Russian embassy denied it was a "planned action by the Russian security services".

Mr Bryant told the BBC's Daily Politics programme he believed had been deaths of Russian exiles on British soil that had not been fully investigated for fear of upsetting diplomatic relations.