The Federal Bureau of Investigation has concluded Hillary Clinton was “extremely careless” in handling top secret emails while secretary of state but recommended against prosecuting the Democratic presidential candidate.

James Comey, the FBI director, said investigators had found 110 emails where Mrs Clinton had either sent or received classified information on her private account. That conclusion contradicted multiple statements by Mrs Clinton that she had never transmitted information marked as secret at the time it was sent.

Still, Mr Comey said his investigators found no evidence Mrs Clinton “intended to violate laws” and that there was no precedent of senior officials facing criminal charges for similar offences — although he acknowledged such breaches in the past had led to “security or administrative actions” rather than prosecution.