A former contemporary of Boris Johnson at Eton and Oxford is in line to take over as chief of MI6 this year as another contender has secured a top diplomatic posting, it is understood.

Tom Hurd, 55, the director-general at the Office for Security and Counter-Terrorism (OSCT), is thought to be a frontrunner to become the next “C” from late summer.

While the formal process to select a successor to Sir Alex Younger has not yet concluded, Mr Hurd is said to be highly rated by Downing Street.

Dame Karen Pierce, the UK’s permanent representative at the UN who had also been considered a frontrunner for the position, was named as the next British ambassador to the US yesterday.

Mr Hurd’s role heading