MI6 codebreaker Gareth Williams was probably killed but the “spy in the bag” case might never be solved after mistakes by investigators, an inquest has heard.

Specks of mystery DNA were discovered on the bag encasing the curled-up body of MI6 spy Gareth Williams, an inquest heard.

An MI6 spy found dead in a padlocked sports bag had been unhappy living in London and complained about “friction” at the intelligence agency, an inquest has heard.